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1.
A Three‐Dimensionally Interconnected Carbon Nanotube–Conducting Polymer Hydrogel Network for High‐Performance Flexible Battery Electrodes
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Zheng Chen John W. F. To Chao Wang Zhenda Lu Nan Liu Alex Chortos Lijia Pan Fei Wei Yi Cui Zhenan Bao 《Liver Transplantation》2014,4(12)
High‐performance flexible energy‐storage devices have great potential as power sources for wearable electronics. One major limitation to the realization of these applications is the lack of flexible electrodes with excellent mechanical and electrochemical properties. Currently employed batteries and supercapacitors are mainly based on electrodes that are not flexible enough for these purposes. Here, a three‐dimensionally interconnected hybrid hydrogel system based on carbon nanotube (CNT)‐conductive polymer network architecture is reported for high‐performance flexible lithium ion battery electrodes. Unlike previously reported conducting polymers (e.g., polyaniline, polypyrrole, polythiophene), which are mechanically fragile and incompatible with aqueous solution processing, this interpenetrating network of the CNT‐conducting polymer hydrogel exibits good mechanical properties, high conductivity, and facile ion transport, leading to facile electrode kinetics and high strain tolerance during electrode volume change. A high‐rate capability for TiO2 and high cycling stability for SiNP electrodes are reported. Typically, the flexible TiO2 electrodes achieved a capacity of 76 mAh g–1 in 40 s of charge/discharge and a high areal capacity of 2.2 mAh cm–2 can be obtained for flexible SiNP‐based electrodes at 0.1C rate. This simple yet efficient solution process is promising for the fabrication of a variety of high performance flexible electrodes. 相似文献
2.
Kyu‐Young Park Jin‐Myoung Lim Norman S. Luu Julia R. Downing Shay G. Wallace Lindsay E. Chaney Hocheon Yoo Woo Jin Hyun Hyeong‐U Kim Mark C. Hersam 《Liver Transplantation》2020,10(25)
To achieve the high energy densities demanded by emerging technologies, lithium battery electrodes need to approach the volumetric and specific capacity limits of their electrochemically active constituents, which requires minimization of the inactive components of the electrode. However, a reduction in the percentage of inactive conductive additives limits charge transport within the battery electrode, which results in compromised electrochemical performance. Here, an electrode design that achieves efficient electron and lithium‐ion transport kinetics at exceptionally low conductive additive levels and industrially relevant active material areal loadings is introduced. Using a scalable Pickering emulsion approach, Ni‐rich LiNi0.8Co0.15Al0.05O2 (NCA) cathode powders are conformally coated using only 0.5 wt% of solution‐processed graphene, resulting in an electrical conductivity that is comparable to 5 wt% carbon black. Moreover, the conformal graphene coating mitigates degradation at the cathode surface, thus providing improved electrochemical cycle life. The morphology of the electrodes also facilitates rapid lithium‐ion transport kinetics, which provides superlative rate capability. Overall, this electrode design concurrently approaches theoretical volumetric and specific capacity limits without tradeoffs in cycle life, rate capability, or active material areal loading. 相似文献
3.
While stretchable micro‐supercapacitors (MSCs) have been realized, they have suffered from limited areal electrochemical performance, thus greatly restricting their practical electronic application. Herein, a facile strategy of 3D printing and unidirectional freezing of a pseudoplastic nanocomposite gel composed of Ti3C2Tx MXene nanosheets, manganese dioxide nanowire, silver nanowires, and fullerene to construct intrinsically stretchable MSCs with thick and honeycomb‐like porous interdigitated electrodes is introduced. The unique architecture utilizes thick electrodes and a 3D porous conductive scaffold in conjunction with interacting material properties to achieve higher loading of active materials, larger interfacial area, and faster ion transport for significantly improved areal energy and power density. Moreover, the oriented cellular scaffold with fullerene‐induced slippage cell wall structure prompts the printed electrode to withstand large deformations without breaking or exhibiting obvious performance degradation. When imbued with a polymer gel electrolyte, the 3D‐printed MSC achieves an unprecedented areal capacitance of 216.2 mF cm?2 at a scan rate of 10 mV s?1, and remains stable when stretched up to 50% and after 1000 stretch/release cycles. This intrinsically stretchable MSC also exhibits high rate capability and outstanding areal energy density of 19.2 µWh cm?2 and power density of 58.3 mW cm?2, outperforming all reported stretchable MSCs. 相似文献
4.
The growing demand for advanced energy storage devices with high energy density and high safety has continuously driven the technical upgrades of cell architectures as well as electroactive materials. Designing thick electrodes with more electroactive materials is a promising strategy to improve the energy density of lithium‐ion batteries (LIBs) without alternating the underlying chemistry. However, the progress toward thick, high areal capacity electrodes is severely limited by the sluggish electronic/ionic transport and easy deformability of conventional electrodes. A self‐supported ultrahigh‐capacity and fire‐resistant LiFePO4 (UCFR‐LFP)‐based nanocomposite cathode is demonstrated here. Benefiting from the structural and chemical uniqueness, the UCFR‐LFP electrodes demonstrate exceptional improvements in electrochemical performance and mass loading of active materials, and thermal stability. Notably, an ultrathick UCFR‐LFP electrode (1.35 mm) with remarkably high mass loading of active materials (108 mg cm?2) and areal capacity (16.4 mAh cm?2) is successfully achieved. Moreover, the 1D inorganic binder‐like ultralong hydroxyapatite nanowires (HAP NWs) enable the UCFR‐LFP electrode with excellent thermal stability (structural integrity up to 1000 °C and electrochemical activity up to 750 °C), fire‐resistance, and wide‐temperature operability. Such a unique UCFR‐LFP electrode offers a promising solution for next‐generation LIBs with high energy density, high safety, and wide operating‐temperature window. 相似文献
5.
The present study was undertaken to test for the hypothesis that the rate of development in the capacity for photosynthetic electron transport per unit area (Jmax;A), and maximum carboxylase activity of Rubisco (Vcmax;A) is proportional to average integrated daily quantum flux density (Qint) in a mixed deciduous forest dominated by the shade‐intolerant species Populus tremula L., and the shade‐tolerant species Tilia cordata Mill. We distinguished between the age‐dependent changes in net assimilation rates due to modifications in leaf dry mass per unit area (MA), foliar nitrogen content per unit dry mass (NM), and fractional partitioning of foliar nitrogen in the proteins of photosynthetic electron transport (FB), Rubisco (FR) and in light‐harvesting chlorophyll‐protein complexes (Vcmax;A ∝ MANMFR; Jmax;A ∝ MANMFB). In both species, increases in Jmax;A and Vcmax;A during leaf development were primarily determined by nitrogen allocation to growing leaves, increases in leaf nitrogen partitioning in photosynthetic machinery, and increases in MA. Canopy differences in the rate of development of leaf photosynthetic capacity were mainly controlled by the rate of change in MA. There was only small within‐canopy variation in the initial rate of biomass accumulation per unit Qint (slope of MA versus leaf age relationship per unit Qint), suggesting that canopy differences in the rate of development of Jmax;A and Vcmax;A are directly proportional to Qint. Nevertheless, MA, nitrogen, Jmax;A and Vcmax;A of mature leaves were not proportional to Qint because of a finite MA in leaves immediately after bud‐burst (light‐independent component of MA). MA, leaf chlorophyll contents and chlorophyll : N ratio of mature leaves were best correlated with the integrated average quantum flux density during leaf development, suggesting that foliar photosynthetic apparatus, once developed, is not affected by day‐to‐day fluctuations in Qint. However, for the upper canopy leaves of P. tremula and for the entire canopy of T. cordata, there was a continuous decline in N contents per unit dry mass in mature non‐senescent leaves on the order of 15–20% for a change of leaf age from 40 to 120 d, possibly manifesting nitrogen reallocation to bud formation. The decline in N contents led to similar decreases in leaf photosynthetic capacity and foliar chlorophyll contents. These data demonstrate that light‐dependent variation in the rate of developmental changes in MA determines canopy differences in photosynthetic capacity, whereas foliar photosynthetic apparatus is essentially constant in fully developed leaves. 相似文献
6.
Yijun Chen Yunsong Wang Zhipeng Wang Mingchu Zou Hui Zhang Wenqi Zhao Muhammad Yousaf Liusi Yang Anyuan Cao Ray P. S. Han 《Liver Transplantation》2018,8(19)
Achieving a high areal capacity is essential for the transfer of outstanding laboratory electrode results to commercial applications and also to ensure there exists a capacity matched cathode and anode for a properly tuned battery. Despite intensive efforts, most electrode materials exhibit areal capacities lower than that of the graphite anodes (4 mA h cm?2). An effective and low‐cost approach is reported to attain a high areal capacity via an intense densification by compacting a porous carbon nanotube sponge grafted with Co3O4 nanoparticles. The hybrid sponge can be compacted to a large degree (up to a tenfold densification) while still keeping its structural integrity and the 3D porous network. This method allows achieving a mass loading of up ?to 14.3 mg cm?2 and an areal capacity of 12 mA h cm?2 (at a current density of 200 mA g?1) together with a gravimetric capacity of >800 mA h g?1. This densification by compaction approach offers an effective and low‐cost strategy to develop high mass loading and areal capacity electrodes for practical energy storage systems. 相似文献
7.
Alexander G. Ivanov Prafullachandra Sane Vaughan Hurry Marianna Król Dimitry Sveshnikov Norman P. A. Huner Gunnar Öquist 《Physiologia plantarum》2003,119(3):376-383
Although it has been well established that acclimation to low growth temperatures is strongly correlated with an increased proportion of reduced QA in all photosynthetic groups, the precise mechanism controlling the redox state of QA and its physiological significance in developing cold tolerance in photoautotrophs has not been fully elucidated. Our recent thermoluminescence (TL) measurements of the acceptor site of PSII have revealed that short‐term exposure of the cyanobacterium Synechococcus sp. PCC 7942 to cold stress, overwintering of Scots pine (Pinus sylvestris L.), and acclimation of Arabidopsis plants to low growth temperatures, all caused a substantial shift in the characteristic TM of S2QB– recombination to lower temperatures. These changes were accompanied by much lower overall TL emission, restricted electron transfer between QA and QB, and in Arabidopsis by a shift of the S2QA–‐related peak to higher temperatures. The shifts in recombination temperatures are indicative of a lower activation energy for the S2QB– redox pair and a higher activation energy for the S2QA– redox pair. This results in an increase in the free‐energy gap between P680+QA– and P680+Pheo– and a narrowing of the free energy gap between QA and QB electron acceptors. We propose that these effects result in an increased population of reduced QA (QA–), facilitating non‐radiative P680+QA– radical pair recombination within the PSII reaction centre. The proposed reaction centre quenching could be an important protective mechanism in cyanobacteria in which antenna and zeaxanthin cycle‐dependent quenching are not present. In herbaceous plants, the enhanced capacity for dissipation of excess light energy via PSII reaction centre quenching following cold acclimation may complement their capacity for increased utilization of absorbed light through CO2 assimilation and carbon metabolism. During overwintering of evergreens, when photosynthesis is inhibited, PSII reaction centre quenching may complement non‐photochemical quenching within the light‐harvesting antenna when zeaxanthin cycle‐dependent energy quenching is thermodynamically restricted by low temperatures. We suggest that PSII reaction centre quenching is a significant mechanism enabling cold‐acclimated organisms to acquire increased resistance to high light. 相似文献
8.
3D‐Printed Cathodes of LiMn1−xFexPO4 Nanocrystals Achieve Both Ultrahigh Rate and High Capacity for Advanced Lithium‐Ion Battery
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Jiangtao Hu Yi Jiang Suihan Cui Yandong Duan Tongchao Liu Hua Guo Lingpiao Lin Yuan Lin Jiaxin Zheng Khalil Amine Feng Pan 《Liver Transplantation》2016,6(18)
A 3D‐printing technology and printed 3D lithium‐ion batteries (3D‐printed LIBs) based on LiMn0.21Fe0.79PO4@C (LMFP) nanocrystal cathodes are developed to achieve both ultrahigh rate and high capacity. Coin cells with 3D‐printed cathodes show impressive electrochemical performance: a capacity of 108.45 mAh g?1 at 100 C and a reversible capacity of 150.21 mAh g?1 at 10 C after 1000 cycles. In combination with simulation using a pseudo 2D hidden Markov model and experimental data of 3D‐printed and traditional electrodes, for the first time deep insight into how to achieve the ultrahigh rate performance for a cathode with LMFP nanocrystals is obtained. It is estimated that the Li‐ion diffusion in LMFP nanocrystal is not the rate‐limitation step for the rate to 100 C, however, that the electrolyte diffusion factors, such as solution intrinsic diffusion coefficient, efficiency porosity, and electrode thickness, will dominate ultrahigh rate performance of the cathode. Furthermore, the calculations indicate that the above factors play important roles in the equivalent diffusion coefficient with the electrode beyond a certain thickness, which determines the whole kinetic process in LIBs. This fundamental study should provide helpful guidance for future design of LIBs with superior electrochemical performance. 相似文献
9.
Abhinav M. Gaikwad Brian V. Khau Greg Davies Benjamin Hertzberg Daniel A. Steingart Ana Claudia Arias 《Liver Transplantation》2015,5(3)
Early demonstrations of wearable devices have driven interest in flexible lithium‐ion batteries. Previous demonstrations of flexible lithium‐ion batteries trade off between low areal capacity, poor mechanical flexibility and/or high thickness of inactive components. Here, a reinforced electrode design is used to support the active layers of the battery and a freestanding carbon nanotube (CNT) layer is used as the current collector. The supported architecture helps to increase the areal capacity (mAh cm‐2) of the battery and improve the tensile strength and mechanical flexibility of the electrodes. Batteries based on lithium cobalt oxide and lithium titanate oxide shows excellent electrochemical and mechanical performance. The battery has an areal capacity of ≈1 mAh cm‐2 and a capacity retention of around 94% after cycling the battery for 450 cycles at a C/2 rate. The reinforced electrode has a tensile strength of ≈5.5–7.0 MPa and shows excellent capacity retention after repeatedly flexing to a bending radius ranging from 45 to 10 mm. The relationships between mechanical flexing, electrochemical performance, and mechanical integrity of the battery are studied using electrochemical cycling, electron microscopy, and electrochemical impedance spectroscopy (EIS). 相似文献
10.
Dan Luo Gaoran Li Ya‐Ping Deng Zhen Zhang Jingde Li Ruilin Liang Matthew Li Yi Jiang Weiwei Zhang Yangshuai Liu Wen Lei Aiping Yu Zhongwei Chen 《Liver Transplantation》2019,9(18)
Lithium–sulfur (Li–S) batteries have great promise to support the next‐generation energy storage if their sluggish redox kinetics and polysulfide shuttling can be addressed. The rational design of sulfur electrodes plays key roles in tacking these problems and achieving high‐efficiency sulfur electrochemistry. Herein, a synergetic defect and architecture engineering strategy to design highly disordered spinel Ni–Co oxide double‐shelled microspheres (NCO‐HS), which consist of defective spinel NiCo2O4–x (x = 0.9 if all nickel is Ni2+ and cobalt is Co2.13+), as the multifunctional sulfur host material is reported. The in situ constructed cation and anion defects endow the NCO‐HS with significantly enhanced electronic conductivity and superior polysulfide adsorbability. Meanwhile, the delicate nanoconstruction offers abundant active interfaces and reduced ion diffusion pathways for efficient Li–S chemistry. Attributed to these synergistic features, the sulfur composite electrode achieves excellent rate performance up to 5 C, remarkable cycling stability over 800 cycles and good areal capacity of 6.3 mAh cm?2 under high sulfur loading. This proposed strategy based on synergy engineering could also inform material engineering in related energy storage and conversion fields. 相似文献
11.
Yolk–Shell NiS2 Nanoparticle‐Embedded Carbon Fibers for Flexible Fiber‐Shaped Sodium Battery
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Fiber‐shaped rechargeable batteries hold promise as the next‐generation energy storage devices for wearable electronics. However, their application is severely hindered by the difficulty in fabrication of robust fiber‐like electrodes with promising electrochemical performance. Herein, yolk–shell NiS2 nanoparticles embedded in porous carbon fibers (NiS2?PCF) are successfully fabricated and developed as high‐performance fiber electrodes for sodium storage. Benefiting from the robust embedded structure, 3D porous and conductive carbon network, and yolk–shell NiS2 nanoparticles, the as‐prepared NiS2?PCF fiber electrode achieves a high reversible capacity of about 679 mA h g?1 at 0.1 C, outstanding rate capability (245 mA h g?1 at 10 C), and ultrastable cycle performance with 76% capacity retention over 5000 cycles at 5 C. Notably, a flexible fiber‐shaped sodium battery is assembled, and high reversible capacity is kept at different bending states. This work offers a new electrode‐design paradigm toward novel carbon fiber electrodes embedded with transition metal oxides/sulfides/phosphides for application in flexible energy storage devices. 相似文献
12.
Hierarchical Zn–Co–S Nanowires as Advanced Electrodes for All Solid State Asymmetric Supercapacitors
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A facile two‐step strategy is developed to design the large‐scale synthesis of hierarchical, unique porous architecture of ternary metal hydroxide nanowires grown on porous 3D Ni foam and subsequent effective sulfurization. The hierarchical Zn–Co–S nanowires (NWs) arrays are directly employed as an electrode for supercapacitors application. The as‐synthesized Zn–Co–S NWs deliver an ultrahigh areal capacity of 0.9 mA h cm?2 (specific capacity of 366.7 mA h g?1) at a current density of 3 mA cm?2, with an exceptional rate capability (≈227.6 mA h g?1 at a very high current density of 40 mA cm?2) and outstanding cycling stability (≈93.2% of capacity retention after 10 000 cycles). Most significantly, the assembled Zn–Co–S NWs//Fe2O3@reduced graphene oxide asymmetric supercapacitors with a wide operating potential window of ≈1.6 V yield an ultrahigh volumetric capacity of ≈1.98 mA h cm?3 at a current density of 3 mA cm?2, excellent energy density of ≈81.6 W h kg?1 at a power density of ≈559.2 W kg?1, and exceptional cycling performance (≈92.1% of capacity retention after 10 000 cycles). This general strategy provides an alternative to design the other ternary metal sulfides, making it facile, free‐standing, binder‐free, and cost‐effective ternary metal sulfide‐based electrodes for large‐scale applications in modern electronics. 相似文献
13.
High energy‐density, low‐cost batteries are critically important to a variety of applications ranging from portable electronics to electric vehicles (EVs) and grid‐scale storage. While tremendous research effort has been focused on new materials or chemistries with high energy‐density potential, design innovations such as low‐tortuosity thick electrodes are another promising path toward higher energy density and lower cost. Growing demand for fast‐charging batteries has also highlighted the need for negative electrodes that can accept high rate charging without metal deposition; low tortuosity can be a benefit in this regard. However, a general and scalable fabrication method for low‐tortuosity electrodes is currently lacking. Here an emulsion‐based, magnetic‐alignment approach to producing thick electrodes (>400 µm thickness) with ultrahigh areal capacity (up to ≈14 mAh cm?2 vs 2–4 mAh cm?2 for conventional lithium ion) is reported. The process is demonstrated for LiCoO2 and meso‐carbon microbead graphite. The LiCoO2 cathodes are confirmed to have low tortuosity via DC‐depolarization experiments and deliver high areal capacity (>10 mAh cm?2) in galvanostatic discharge tests at practical C‐rates and model EV drive‐cycle tests. This simple fabrication method can potentially be applied to many other active materials to enable thick, low‐tortuosity electrodes. 相似文献
14.
Qing Zhang Christophe Didier Wei Kong Pang Yajie Liu Zhijie Wang Sean Li Vanessa K. Peterson Jianfeng Mao Zaiping Guo 《Liver Transplantation》2019,9(30)
Potassium‐ion batteries (PIBs) are an emerging, affordable, and environmentally friendly alternative to lithium‐ion batteries, with their further development driven by the need for suitably performing electrode materials capable of reversibly accommodating the relatively large K+. Layer‐structured manganese oxides are attractive as electrodes for PIBs, but suffer from structural instability and sluggish kinetics of K+ insertion/extraction, leading to poor rate capability. Herein, cobalt is successfully introduced at the manganese site in the KxMnO2 layered oxide electrode material and it is shown that with only 5% Co, the reversible capacity increases by 30% at 22 mA g‐1 and by 92% at 440 mA g‐1. In operando synchrotron X‐ray diffraction reveals that Co suppresses Jahn–Teller distortion, leading to more isotropic migration pathways for K+ in the interlayer, thus enhancing the ionic diffusion and consequently, rate capability. The detailed analysis reveals that additional phase transitions and larger volume change occur in the Co‐doped material as a result of layer gliding, with these associated with faster capacity decay, despite the overall capacity remaining higher than the pristine material, even after 500 cycles. These results assert the importance of understanding the detailed structural evolution that underpins performance that will inform the strategic design of electrode materials for high‐performance PIBs. 相似文献
15.
Micro‐ and Nano‐Structured Vanadium Pentoxide (V2O5) for Electrodes of Lithium‐Ion Batteries
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Vanadium pentoxide (V2O5) has played important roles in lithium‐ion batteries due to its unique crystalline structure. To assist researchers understanding the roles this material plays, a comprehensive and critical review is conducted based on about 250 publications. Here, we report basics and applications of micro‐ and nano‐materials of V2O5 and V2O5‐based composites. The comparative and statistical analysis leads to the discovery of several interesting phenomena. The V2O5 electrodes with two lithium ions have a favorable capacity performance with reversible phase formation. The excellent capacity retention is displayed in the V2O5 electrodes with one lithium ion inserted. In the case of three lithium ions insertion, it was found that the irreversible formation of the phase ω in LixV2O5 leads to its control. In addition, effects of additives on electrode performance, circuitry models of performance, as well as reaction routes are studied. Two unprecedented concepts of the “high capacity band” and “empirical total capacity retention” are proposed though the comprehensive statistical analysis of the reviewed data. This review provides a comprehensive collection of information of state‐of‐the‐art and recent advancement in V2O5 and V2O5‐based composite materials for electrodes. Researchers could use the information to design and develop advanced electrodes for future batteries. 相似文献
16.
Hierarchical Fabric Decorated with Carbon Nanowire/Metal Oxide Nanocomposites for 1.6 V Wearable Aqueous Supercapacitors
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Aqueous asymmetric supercapacitors (ASCs) may offer comparable or higher energy density than electric double‐layer capacitors (EDLCs) based on organic electrolytes. As such, ASCs may be more suitable for integration into smart textiles, where the use of flammable organic solvents is not acceptable. However, reported ASC devices typically suffer from poor rate capability and low areal loadings. This study demonstrates the development of nitrogen‐doped carbon (N‐C) nanowire/metal oxide (Fe2O3 and MnO2) nanocomposite electrodes directly produced on the internal surface of a conductive fabric for use as high‐rate electrodes for solid‐state ASCs. The N‐C nanowires provide fast and efficient pathways for electrons, while short diffusion paths within nanosized metal oxides enable fast ion transport, leading to greatly enhanced performance at high rates. The porous structure of the fabric enables high areal capacitance loading in each electrode (≈150 mF cm?2). Both electrodes show high specific capacitance of ≈180 F g?1 (Fe2O3) and ≈250 F g?1 (MnO2) and excellent rate capability. Solid‐state ASCs assembled by using an aqueous gel electrolyte operate at 1.6 V and deliver over 60 mF cm?2 during ≈50 s charging/discharging time and over 30 mF cm?2 for ≈5 s discharge. 相似文献
17.
Carbon/Binder‐Free NiO@NiO/NF with In Situ Formed Interlayer for High‐Areal‐Capacity Lithium Storage
Yan‐Fei Li Yan‐Hong Shi Shu‐Guang Wang Jin‐Hua Liu Jian Lin Yu Xia Xing‐Long Wu Chao‐Ying Fan Jing‐Ping Zhang Hai‐Ming Xie Hai‐Zhu Sun Zhong‐Min Su 《Liver Transplantation》2019,9(14)
Achieving high areal capacity is a challenge for current lithium‐ion batteries (LIBs). To address this issue, nickel foam (NF), as a free‐standing skeleton suffers from long‐term poor anchor ability for active materials, resulting in detachment from conductive substrates. In addition, the weighty NF damages the overall energy density of the electrode. Herein, an in situ fabrication of interlayer strategy is proposed to effectively address these issues through constructing layer‐by‐layer a 3D structure composed of an inner conductive framework, medial NiO layer, and outer few‐layer NiO nanoflowers in turn (NiO@NiO/NF). The interlayer derived from partial oxidation of NF not only reinforces the attachment of the active layer on NF but also contributes capacity to the whole electrode, leading to excellent stability and areal capacity. When used as the anode of LIBs, ultrahigh reversible capacity of 1.98 mAh cm?2 is delivered at 1.20 mA cm?2. The electrode still maintains good integrity and flexibility after 1000 cycles, showing good structure stability. Compared with previous reports, NiO@NiO/NF is one of the most outstanding NiO‐based electrodes. This work proposes a feasible strategy to enhance the capacity and stability of self‐supporting electrodes, and opens a new avenue for high‐areal‐capacity anode of LIBs. 相似文献
18.
Exceptionally Enhanced Electrode Activity of (Pr,Ce)O2−δ‐Based Cathodes for Thin‐Film Solid Oxide Fuel Cells
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It is shown that an electrochemically‐driven oxide overcoating substantially improves the performance of metal electrodes in high‐temperature electrochemical applications. As a case study, Pt thin films are overcoated with (Pr,Ce)O2?δ (PCO) by means of a cathodic electrochemical deposition process that produces nanostructured oxide layers with a high specific surface area and uniform metal coverage and then the coated films are examined as an O2‐electrode for thin‐film‐based solid oxide fuel cells. The combination of excellent conductivity, reactivity, and durability of PCO dramatically improves the oxygen reduction reaction rate while maintaining the nanoscale architecture of PCO layers and thus the performance of the PCO‐coated Pt thin‐film electrodes at high temperatures. As a result, with an oxide coating step lasting only 5 min, the electrode resistance is successfully reduced by more than 1000 times at 500 °C in air. These observations provide a new direction for the design of high‐performance electrodes for high‐temperature electrochemical cells. 相似文献
19.
MoS2 Nanosheets Vertically Aligned on Carbon Paper: A Freestanding Electrode for Highly Reversible Sodium‐Ion Batteries
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Xiuqiang Xie Taron Makaryan Mengqiang Zhao Katherine L. Van Aken Yury Gogotsi Guoxiu Wang 《Liver Transplantation》2016,6(5)
The development of sodium‐ion batteries for large‐scale applications requires the synthesis of electrode materials with high capacity, high initial Coulombic efficiency (ICE), high rate performance, long cycle life, and low cost. A rational design of freestanding anode materials is reported for sodium‐ion batteries, consisting of molybdenum disulfide (MoS2) nanosheets aligned vertically on carbon paper derived from paper towel. The hierarchical structure enables sufficient electrode/electrolyte interaction and fast electron transportation. Meanwhile, the unique architecture can minimize the excessive interface between carbon and electrolyte, enabling high ICE. The as‐prepared MoS2@carbon paper composites as freestanding electrodes for sodium‐ion batteries can liberate the traditional electrode manufacturing procedure, thereby reducing the cost of sodium‐ion batteries. The freestanding MoS2@carbon paper electrode exhibits a high reversible capacity, high ICE, good cycling performance, and excellent rate capability. By exploiting in situ Raman spectroscopy, the reversibility of the phase transition from 2H‐MoS2 to 1T‐MoS2 is observed during the sodium‐ion intercalation/deintercalation process. This work is expected to inspire the development of advanced electrode materials for high‐performance sodium‐ion batteries. 相似文献
20.
Facile Synthesis of a 3D Nanoarchitectured Li4Ti5O12 Electrode for Ultrafast Energy Storage
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Despite enormous efforts devoted to the development of high‐performance batteries, the obtainable energy and power density, durability, and affordability of the existing batteries are still inadequate for many applications. Here, a self‐standing nanostructured electrode with ultrafast cycling capability is reported by in situ tailoring Li4Ti5O12 nanocrystals into a 3D carbon current collector (derived from filter paper) through a facile wet chemical process involving adsorption of titanium source, boiling treatment, and subsequent chemical lithiation. This 3D architectural electrode is charged/discharged to ≈60% of the theoretical capacity of Li4Ti5O12 in ≈21 s at 100 C rate (17 500 mA g?1 ), which also shows stable cycling performance for 1000 cycles at a cycling rate of 50 C. Additionally, modified 3D carbon current collector with much smaller pores and finer fiber diameters are further used, which significantly improve the specific capacity based on the weight of the entire electrode. These novel electrodes are promising for high‐power applications such as electric vehicles and smart grids. This unique electrode architecture also simplifies the electrode fabrication process and significantly enhances current collection efficiency (especially at high rate). Further, the conceptual electrode design is applicable to other oxide electrode materials for high‐performance batteries, fuel cells, and supercapacitors. 相似文献