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1.
Seok Hyun Song Moses Cho Inchul Park Jong‐Gyu Yoo Kyung‐Tae Ko Jihyun Hong Jongsoon Kim Sung‐Kyun Jung Maxim Avdeev Sungdae Ji Seongsu Lee Joona Bang Hyungsub Kim 《Liver Transplantation》2020,10(23)
Layered lithium–nickel–cobalt–manganese oxide (NCM) materials have emerged as promising alternative cathode materials owing to their high energy density and electrochemical stability. Although high reversible capacity has been achieved for Ni‐rich NCM materials when charged beyond 4.2 V versus Li+/Li, full lithium utilization is hindered by the pronounced structural degradation and electrolyte decomposition. Herein, the unexpected realization of sustained working voltage as well as improved electrochemical performance upon electrochemical cycling at a high operating voltage of 4.9 V in the Ni‐rich NCM LiNi0.895Co0.085Mn0.02O2 is presented. The improved electrochemical performance at a high working voltage at 4.9 V is attributed to the removal of the resistive Ni2+O rock‐salt surface layer, which stabilizes the voltage profile and improves retention of the energy density during electrochemical cycling. The manifestation of the layered Ni2+O rock‐salt phase along with the structural evolution related to the metal dissolution are probed using in situ X‐ray diffraction, neutron diffraction, transmission electron microscopy, and X‐ray absorption spectroscopy. The findings help unravel the structural complexities associated with high working voltages and offer insight for the design of advanced battery materials, enabling the realization of fully reversible lithium extraction in Ni‐rich NCM materials. 相似文献
2.
Weibo Hua Mingzhe Chen Bjrn Schwarz Michael Knapp Michael Bruns Juri Barthel Xiushan Yang Florian Sigel Raheleh Azmi Anatoliy Senyshyn Alkesandr Missiul Laura Simonelli Martin Etter Suning Wang Xiaoke Mu Andy Fiedler Joachim R. Binder Xiaodong Guo Shulei Chou Benhe Zhong Sylvio Indris Helmut Ehrenberg 《Liver Transplantation》2019,9(8)
As promising cathode materials, the lithium‐excess 3d‐transition‐metal layered oxides can deliver much higher capacities (>250 mAh g?1 at 0.1 C) than the current commercial layered oxide materials (≈180 mAh g?1 at 0.1 C) used in lithium ion batteries. Unfortunately, the original formation mechanism of these layered oxides during synthesis is not completely elucidated, that is, how is lithium and oxygen inserted into the matrix structure of the precursor during lithiation reaction? Here, a promising and practical method, a coprecipitation route followed by a microwave heating process, for controllable synthesis of cobalt‐free lithium‐excess layered compounds is reported. A series of the consistent results unambiguously confirms that oxygen atoms are successively incorporated into the precursor obtained by a coprecipitation process to maintain electroneutrality and to provide the coordination sites for inserted Li ions and transition metal cations via a high‐temperature lithiation. It is found that the electrochemical performances of the cathode materials are strongly related to the phase composition and preparation procedure. The monoclinic layered Li[Li0.2Ni0.2Mn0.6]O2 cathode materials with state‐of‐the‐art electrochemical performance and comparably high discharge capacities of 171 mAh g?1 at 10 C are obtained by microwave annealing at 750 °C for 2 h. 相似文献
3.
Iron oxides, such as Fe2O3 and Fe3O4, have recently received increased attention as very promising anode materials for rechargeable lithium‐ion batteries (LIBs) because of their high theoretical capacity, non‐toxicity, low cost, and improved safety. Nanostructure engineering has been demonstrated as an effective approach to improve the electrochemical performance of electrode materials. Here, recent research progress in the rational design and synthesis of diverse iron oxide‐based nanomaterials and their lithium storage performance for LIBs, including 1D nanowires/rods, 2D nanosheets/flakes, 3D porous/hierarchical architectures, various hollow structures, and hybrid nanostructures of iron oxides and carbon (including amorphous carbon, carbon nanotubes, and graphene). By focusing on synthesis strategies for various iron‐oxide‐based nanostructures and the impacts of nanostructuring on their electrochemical performance, novel approaches to the construction of iron‐oxide‐based nanostructures are highlighted and the importance of proper structural and compositional engineering that leads to improved physical/chemical properties of iron oxides for efficient electrochemical energy storage is stressed. Iron‐oxide‐based nanomaterials stand a good chance as negative electrodes for next generation LIBs. 相似文献
4.
Defei Kong Jiangtao Hu Zhefeng Chen Kepeng Song Cheng Li Mouyi Weng Maofan Li Rui Wang Tongchao Liu Jiajie Liu Mingjian Zhang Yinguo Xiao Feng Pan 《Liver Transplantation》2019,9(41)
High‐Ni layered oxide cathodes are considered to be one of the most promising cathodes for high‐energy‐density lithium‐ion batteries due to their high capacity and low cost. However, surfice residues, such as NiO‐type rock‐salt phase and Li2CO3, are often formed at the particle surface due to the high reactivity of Ni3+, and inevitably result in an inferior electrochemical performance, hindering the practical application. Herein, unprecedentedly clean surfaces without any surfice residues are obtained in a representative LiNi0.8Co0.2O2 cathode by Ti‐gradient doping. High‐resolution transmission electron microscopy (TEM) reveals that the particle surface is composed of a disordered layered phase (≈6 nm in thickness) with the same rhombohedra structure as its interior. The formation of this disordered layered phase at the particle surface is electrochemically favored. It leads to the highest rate capacity ever reported and a superior cycling stability. First‐principles calculations further confirm that the excellent electrochemical performance has roots in the excellent chemical/structural stability of such a disordered layered structure, mainly arising from the improved robustness of the oxygen framework by Ti doping. This strategy of constructing the disordered layered phase at the particle surface could be extended to other high‐Ni layered transition metal oxides, which will contribute to the enhancement of their electrochemical performance. 相似文献
5.
Junghwa Lee Qinghua Zhang Jieun Kim Nicolas Dupre Maxim Avdeev Mihee Jeong Won‐Sub Yoon Lin Gu Byoungwoo Kang 《Liver Transplantation》2020,10(5)
The quest for high energy density and high power density electrode materials for lithium‐ion batteries has been intensified to meet strongly growing demand for powering electric vehicles. Conventional layered oxides such as Co‐rich LiCoO2 and Ni‐rich Li(NixMnyCoz)O2 that rely on only transition metal redox reaction have been faced with growing constraints due to soaring price on cobalt. Therefore, Mn‐rich electrode materials excluding cobalt would be desirable with respect to available resources and low cost. Here, the strategy of achieving both high energy density and high power density in Mn‐rich electrode materials by controlling the solubility of atoms between phases in a composite is reported. The resulting Mn‐rich material that is composed of defective spinel phase and partially cation‐disordered layered phase can achieve the highest energy density, ≈1100 W h kg?1 with superior power capability up to 10C rate (3 A g?1) among other reported Mn‐rich materials. This approach provides new opportunities to design Mn‐rich electrode materials that can achieve high energy density and high power density for Li‐ion batteries. 相似文献
6.
Shuai Liu Zepeng Liu Xi Shen Xuelong Wang Sheng‐Chieh Liao Richeng Yu Zhaoxiang Wang Zhiwei Hu Chien‐Te Chen Xiqian Yu Xiaoqing Yang Liquan Chen 《Liver Transplantation》2019,9(32)
Li‐rich layered metal oxides are one type of the most promising cathode materials in lithium‐ion batteries but suffer from severe voltage decay during cycling because of the continuous transition metal (TM) migration into the Li layers. A Li‐rich layered metal oxide Li1.2Ti0.26Ni0.18Co0.18Mn0.18O2 (LTR) is hereby designed, in which some of the Ti4+ cations are intrinsically present in the Li layers. The native Li–Ti cation mixing structure enhances the tolerance for structural distortion and inhibits the migration of the TM ions in the TMO2 slabs during (de)lithiation. Consequently, LTR exhibits a remarkable cycling stability of 97% capacity retention after 182 cycles, and the average discharge potential drops only 90 mV in 100 cycles. In‐depth studies by electron energy loss spectroscopy and aberration‐corrected scanning transmission electron microscopy demonstrate the Li–Ti mixing structure. The charge compensation mechanism is uncovered with X‐ray absorption spectroscopy and explained with the density function theory calculations. These results show the superiority of introducing transition metal ions into the Li layers in reinforcing the structural stability of the Li‐rich layered metal oxides. These findings shed light on a possible path to the development of Li‐rich materials with better potential retention and a longer lifespan. 相似文献
7.
An Ion‐Exchange Promoted Phase Transition in a Li‐Excess Layered Cathode Material for High‐Performance Lithium Ion Batteries
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Jianqing Zhao Ruiming Huang Wenpei Gao Jian‐Min Zuo Xiao Feng Zhang Scott T. Misture Yuan Chen Jenny V. Lockard Boliang Zhang Shengmin Guo Mohammad Reza Khoshi Kerry Dooley Huixin He Ying Wang 《Liver Transplantation》2015,5(9)
A new approach to intentionally induce phase transition of Li‐excess layered cathode materials for high‐performance lithium ion batteries is reported. In high contrast to the limited layered‐to‐spinel phase transformation that occurred during in situ electrochemical cycles, a Li‐excess layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is completely converted to a Li4Mn5O12‐type spinel product via ex situ ion‐exchanges and a post‐annealing process. Such a layered‐to‐spinel phase conversion is examined using in situ X‐ray diffraction and in situ high‐resolution transmission electron microscopy. It is found that generation of sufficient lithium ion vacancies within the Li‐excess layered oxide plays a critical role for realizing a complete phase transition. The newly formed spinel material exhibits initial discharge capacities of 313.6, 267.2, 204.0, and 126.3 mAh g?1 when cycled at 0.1, 0.5, 1, and 5 C (1 C = 250 mA g?1), respectively, and can retain a specific capacity of 197.5 mAh g?1 at 1 C after 100 electrochemical cycles, demonstrating remarkably improved rate capability and cycling stability in comparison with the original Li‐excess layered cathode materials. This work sheds light on fundamental understanding of phase transitions within Li‐excess layered oxides. It also provides a novel route for tailoring electrochemical performance of Li‐excess layered cathode materials for high‐capacity lithium ion batteries. 相似文献
8.
Suppression of Voltage Decay through Manganese Deactivation and Nickel Redox Buffering in High‐Energy Layered Lithium‐Rich Electrodes
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Kyojin Ku Jihyun Hong Hyungsub Kim Hyeokjun Park Won Mo Seong Sung‐Kyun Jung Gabin Yoon Kyu‐Young Park Haegyeom Kim Kisuk Kang 《Liver Transplantation》2018,8(21)
Cobalt‐free layered lithium‐rich nickel manganese oxides, Li[LixNiyMn1?x?y]O2 (LLNMO), are promising positive electrode materials for lithium rechargeable batteries because of their high energy density and low materials cost. However, substantial voltage decay is inevitable upon electrochemical cycling, which makes this class of materials less practical. It has been proposed that undesirable voltage decay is linked to irreversible structural rearrangement involving irreversible oxygen loss and cation migration. Herein, the authors demonstrate that the voltage decay of the electrode is correlated to Mn4+/Mn3+ redox activation and subsequent cation disordering, which can be remarkably suppressed via simple compositional tuning to induce the formation of Ni3+ in the pristine material. By implementing our new strategy, the Mn4+/Mn3+ reduction is subdued by an alternative redox reaction involving the use of pristine Ni3+ as a redox buffer, which has been designed to be widened from Ni3+/Ni4+ to Ni2+/Ni4+, without compensation for the capacity in principle. Negligible change in the voltage profile of modified LLNMO is observed upon extended cycling, and manganese migration into the lithium layer is significantly suppressed. Based on these findings, we propose a general strategy to suppress the voltage decay of Mn‐containing lithium‐rich oxides to achieve long‐lasting high energy density from this class of materials. 相似文献
9.
Miao Han Junyu Jiao Zepeng Liu Xi Shen Qinghua Zhang Hong‐Ji Lin Chien‐Te Chen Qingyu Kong Wei Kong Pang Zaiping Guo Richeng Yu Lin Gu Zhiwei Hu Zhaoxiang Wang Liquan Chen 《Liver Transplantation》2020,10(8)
Lithium‐rich layered oxides are promising candidate cathode materials for the Li‐ion batteries with energy densities above 300 Wh kg?1. However, issues such as the voltage hysteresis and decay hinder their commercial applications. Due to the entanglement of the transition metal (TM) migration and the anionic redox upon lithium extraction at high potentials, it is difficult to recognize the origin of these issues in conventional Li‐rich layered oxides. Herein, Li2MoO3 is chosen since prototype material to uncover the reason for the voltage hysteresis as the TM migration and anionic redox can be eliminated below 3.6 V versus Li+/Li in this material. On the basis of comprehensive investigations by neutron powder diffraction, scanning transmission electron microscopy, synchrotron X‐ray absorption spectroscopy, and density functional theory calculations, it is clarified that the ordering–disordering transformation of the Mo3O13 clusters induced by the intralayer Mo migration is responsible for the voltage hysteresis in the first cycle; the hysteresis can take place even without the anionic redox or the interlayer Mo migration. A similar suggestion is drawn for its iso‐structured Li2RuO3 (C2/c). These findings are useful for understanding of the voltage hysteresis in other complicated Li‐rich layered oxides. 相似文献
10.
Computational Design and Preparation of Cation‐Disordered Oxides for High‐Energy‐Density Li‐Ion Batteries
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Cation‐disordered lithium‐excess metal oxides have recently emerged as a promising new class of high‐energy‐density cathode materials for Li‐ion batteries, but the exploration of disordered materials has been hampered by their vast and unexplored composition space. This study proposes a practical methodology for the identification of stable cation‐disordered rocksalts. Here, it is established that the efficient method, which makes use of special quasirandom structures, correctly predicts cation‐ordering strengths in agreement with accurate Monte‐Carlo simulations and experimental observations. By applying the approach to the composition space of ternary oxides with formula unit LiA0.5B0.5O2 (A, B: transition metals), this study discovers a previously unknown cation‐disordered structure, LiCo0.5Zr0.5O2, that may function as the basis for a new class of cation‐disordered cathode materials. This computational prediction is confirmed experimentally by solid‐state synthesis and subsequent characterization by powder X‐ray diffraction demonstrating the potential of the computational screening of large composition spaces for accelerating materials discovery. 相似文献
11.
Doped‐MoSe2 Nanoflakes/3d Metal Oxide–Hydr(Oxy)Oxides Hybrid Catalysts for pH‐Universal Electrochemical Hydrogen Evolution Reaction
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Leyla Najafi Sebastiano Bellani Reinier Oropesa‐Nuñez Alberto Ansaldo Mirko Prato Antonio Esau Del Rio Castillo Francesco Bonaccorso 《Liver Transplantation》2018,8(27)
Clean hydrogen production is highly promising to meet future global energy demands. The design of earth‐abundant materials with both high activity for hydrogen evolution reaction (HER) and electrochemical stability in both acidic and alkaline environments is needed, in order to enable practical applications. Here, the authors report a non‐noble 3d metal Cl‐chemical doping of liquid phase exfoliated single‐/few‐layer flakes of MoSe2 for creating MoSe2/3d metal oxide–hydr(oxy)oxide hybrid HER‐catalysts. It is proposed that the electron‐transfer from MoSe2 nanoflakes to metal cations and the chlorine complexation‐induced neutralization, as well as the in situ formation of metal oxide–hydr(oxy)oxides on the MoSe2 nanoflakes' surface, tailor the proton affinity of the catalysts, increasing the number and HER‐kinetics of their active sites in both acidic and alkaline electrolytes. The electrochemical coupling between doped‐MoSe2/metal oxide–hydr(oxy)oxide hybrids and single‐walled carbon nanotubes heterostructures further accelerates the HER process. Lastly, monolithic stacking of multiple heterostructures is reported as a facile electrode assembly strategy to achieve overpotential for a cathodic current density of 10 mA cm?2 of 0.081 and 0.064 V in 0.5 m H2SO4 and 1 m KOH, respectively. This opens up new opportunities to address the current density versus overpotential requirements targeted in pH‐universal hydrogen production. 相似文献
12.
Jun‐Hyuk Song Gabin Yoon Byunghoon Kim Donggun Eum Hyeokjun Park Do‐Hoon Kim Kisuk Kang 《Liver Transplantation》2020,10(31)
The anionic redox activity in lithium‐rich layered oxides has the potential to boost the energy density of lithium‐ion batteries. Although it is widely accepted that the anionic redox activity stems from the orphaned oxygen energy level, its regulation and structural stabilization, which are essential for practical employment, remain still elusive, requiring an improved fundamental understanding. Herein, the oxygen redox activity for a wide range of 3d transition‐metal‐based Li2TMO3 compounds is investigated and the intrinsic competition between the cationic and anionic redox reaction is unveiled. It is demonstrated that the energy level of the orphaned oxygen state (and, correspondingly, the activity) is delicately governed by the type and number of neighboring transition metals owing to the π‐type interactions between Li? O? Li and M t2g states. Based on these findings, a simple model that can be used to estimate the anionic redox activity of various lithium‐rich layered oxides is proposed. The model explains the recently reported significantly different oxygen redox voltages or inactivity in lithium‐rich materials despite the commonly observed Li? O? Li states with presumably unhybridized character. The discovery of hidden factors that rule the anionic redox in lithium‐rich cathode materials will aid in enabling controlled cumulative cationic and anionic redox reactions. 相似文献
13.
Yejing Li Xuefeng Wang Yurui Gao Qinghua Zhang Guoqiang Tan Qingyu Kong Seongmin Bak Gang Lu Xiao‐Qing Yang Lin Gu Jun Lu Khalil Amine Zhaoxiang Wang Liquan Chen 《Liver Transplantation》2019,9(4)
Cathode materials with high energy density, long cycle life, and low cost are of top priority for energy storage systems. The Li‐rich transition metal (TM) oxides achieve high specific capacities by redox reactions of both the TM and oxygen ions. However, the poor reversible redox reaction of the anions results in severe fading of the cycling performance. Herein, the vacancy‐containing Na4/7[Mn6/7(?Mn)1/7]O2 (?Mn for vacancies in the Mn? O slab) is presented as a novel cathode material for Na‐ion batteries. The presence of native vacancies endows this material with attractive properties including high structural flexibility and stability upon Na‐ion extraction and insertion and high reversibility of oxygen redox reaction. Synchrotron X‐ray absorption near edge structure and X‐ray photoelectron spectroscopy studies demonstrate that the charge compensation is dominated by the oxygen redox reaction and Mn3+/Mn4+ redox reaction separately. In situ synchrotron X‐ray diffraction exhibits its zero‐strain feature during the cycling. Density functional theory calculations further deepen the understanding of the charge compensation by oxygen and manganese redox reactions and the immobility of the Mn ions in the material. These findings provide new ideas on searching for and designing materials with high capacity and high structural stability for novel energy storage systems. 相似文献
14.
Ultrahigh‐Ni layered oxides hold great promise as high‐energy‐density cathodes at an affordable cost for lithium‐ion batteries, yet their practical application is greatly hampered by the poor cyclability. Herein, by employing LiNi0.94Co0.06O2 as a model cathode in a full‐cell configuration, the interphasial and structural evolution processes of ultrahigh‐Ni layered oxides are systematically investigated over the course of their service life (1500 cycles). By applying advanced analytic techniques (e.g., Li‐isotope labeling, region‐of‐interest method), the dynamic chemical evolution on the cathode surface is revealed with spatial resolution, and the correlation between lattice distortion and cathode surface reactivity is established. Benefiting from in situ X‐ray diffraction (XRD) analysis, the ultrahigh‐Ni layered oxide is demonstrated to undergo dual‐phase reaction mechanisms with huge lattice variation, which leads to a decrease in crystallinity and secondary particle pulverization. Furthermore, the critical impact of cathode surface reaction on the graphite anode–electrolyte interphase (AEI) is revealed at nanometer scale, and a universal chemical/physical evolution process of the AEI is illustrated, for the first time. Finally, the practical viability of ultrahigh‐Ni layered oxides is demonstrated through Al‐doping strategy. This work presents a comprehensive understanding of the structural and interphasial degradation of ultrahigh‐Ni layered oxide cathodes for developing high‐energy‐density lithium‐ion batteries. 相似文献
15.
Qidong Li Li Li Peijie Wu Nuo Xu Liang Wang Matthew Li Alvin Dai Khalil Amine Liqiang Mai Jun Lu 《Liver Transplantation》2019,9(43)
Nickel sulfides are regarded as promising anode materials for advanced rechargeable lithium‐ion batteries due to their high theoretical capacity. However, capacity fade arising from significant volume changes during operation greatly limits their practical applications. Herein, confined NiSx@C yolk–shell microboxes are constructed to address volume changes and confine the active material in the internal void space. Having benefited from the yolk–shell structure design, the prepared NiSx@C yolk–shell microboxes display excellent electrochemical performance in lithium‐ion batteries. Particularly, it delivers impressive cycle stability (460 mAh g?1 after 2000 cycles at 1 A g?1) and superior rate performance (225 mAh g?1 at 20 A g?1). Furthermore, the lithium storage mechanism is ascertained with in situ synchrotron high‐energy X‐ray diffractions and in situ electrochemical impedance spectra. This unique confined yolk–shell structure may open up new strategies to create other advanced electrode materials for high performance electrochemical storage systems. 相似文献
16.
Dong‐Hwa Seo Kyu‐Young Park Haegyeom Kim Sung‐Kyun Jung Min‐Sik Park Kisuk Kang 《Liver Transplantation》2018,8(6)
Triplite‐type LiFeSO4F has attracted considerable attention as a promising cathode for next‐generation lithium‐ion batteries because of its high redox potential based on earth‐abundant Fe2+/3+. However, successful extraction/reinsertion of all the lithium ions in triplite host is challenging even at a low current rate, resulting in a low specific capacity. These experimental findings contrast with previous theoretical works that predicted that the triplite structure would be a fast ionic conductor with low activation barriers for lithium‐ion hopping. Origin of this discrepancy is elusive to date. Herein, combined first‐principles calculations and high‐angle annular dark‐field scanning transmission electron microscopy analyses reveal that typical triplite structure is composed of nanodomains consisting of corner‐shared FeO4F2 octahedra, whereas their domain boundaries are regions of mixed corner/edge‐shared FeO4F2 octahedra. More importantly, these locally disordered domain boundaries significantly reduce the overall lithium diffusivity of the materials. Inspired by these findings, this study redesigns triplite structure with sufficiently small sizes to avoid local bottlenecks arising from the domain boundaries, successfully achieving nearly full lithium extraction/reinsertion with high power and energy density. This work represents the first direct observation of the presence of domain boundaries within a crystalline structure playing a critical role in governing the lithium diffusivity in a battery electrode. 相似文献
17.
Jun Zhang Chao Zheng Lujie Li Yang Xia Hui Huang Yongping Gan Chu Liang Xinping He Xinyong Tao Wenkui Zhang 《Liver Transplantation》2020,10(4)
High‐performance rechargeable all‐solid‐state lithium metal batteries with high energy density and enhanced safety are attractive for applications like portable electronic devices and electric vehicles. Among the various solid electrolytes, argyrodite Li6PS5Cl with high ionic conductivity and easy processability is of great interest. However, the low interface compatibility between sulfide solid electrolytes and high capacity cathodes like nickel‐rich layered oxides requires many thorny issues to be resolved, such as the space charge layer (SCL) and interfacial reactions. In this work, in situ electrochemical impedance spectroscopy and in situ Raman spectroscopy measurements are performed to monitor the detailed interface evolutions in a LiNi0.8Co0.1Mn0.1O2 (NCM)/Li6PS5Cl/Li cell. Combining with ex situ characterizations including scanning electron microscopy and X‐ray photoelectron spectroscopy, the evolution of the SCL and the chemical bond vibration at NCM/Li6PS5Cl interface during the early cycles is elaborated. It is found that the Li+ ion migration, which varies with the potential change, is a very significant cause of these interface behaviors. For the long‐term cycling, the SCL, interfacial reactions, lithium dendrites, and chemo‐mechanical failure have an integrated effect on interfaces, further deteriorating the interfacial structure and electrochemical performance. This research provides a new insight on intra and intercycle interfacial evolution of solid‐state batteries. 相似文献
18.
Hierarchical Structures Based on Two‐Dimensional Nanomaterials for Rechargeable Lithium Batteries
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Two‐dimensional (2D) nanomaterials (i.e., graphene and its derivatives, transition metal oxides and transition metal dichalcogenides) are receiving a lot attention in energy storage application because of their unprecedented properties and great diversities. However, their re‐stacking or aggregation during the electrode fabrication process has greatly hindered their further developments and applications in rechargeable lithium batteries. Recently, rationally designed hierarchical structures based on 2D nanomaterials have emerged as promising candidates in rechargeable lithium battery applications. Numerous synthetic strategies have been developed to obtain hierarchical structures and high‐performance energy storage devices based on these hierarchical structure have been realized. This review summarizes the synthesis and characteristics of three styles of hierarchical architecture, namely three‐dimensional (3D) porous network nanostructures, hollow nanostructures and self‐supported nanoarrays, presents the representative applications of hierarchical structured nanomaterials as functional materials for lithium ion batteries, lithium‐sulfur batteries and lithium‐oxygen batteries, meanwhile sheds light particularly on the relationship between structure engineering and improved electrochemical performance; and provides the existing challenges and the perspectives for this fast emerging field. 相似文献
19.
Fanglin Wu Guk‐Tae Kim Matthias Kuenzel Huang Zhang Jakob Asenbauer Dorin Geiger Ute Kaiser Stefano Passerini 《Liver Transplantation》2019,9(43)
The eco‐friendly and low‐cost Co‐free Li1.2Mn0.585Ni0.185Fe0.03O2 is investigated as a positive material for Li‐ion batteries. The electrochemical performance of the 3 at% Fe‐doped material exhibits an optimal performance with a capacity and voltage retention of 70 and 95%, respectively, after 200 cycles at 1C. The effect of iron doping on the electrochemical properties of lithium‐rich layered materials is investigated by means of in situ X‐ray diffraction spectroscopy and galvanostatic intermittent titration technique during the first charge–discharge cycle while high‐resolution transmission electron microscopy is used to follow the structural and chemical change of the electrode material upon long‐term cycling. By means of these characterizations it is concluded that iron doping is a suitable approach for replacing cobalt while mitigating the voltage and capacity degradation of lithium‐rich layered materials. Finally, complete lithium‐ion cells employing Li1.2Mn0.585Ni0.185Fe0.03O2 and graphite show a specific energy of 361 Wh kg?1 at 0.1C rate and very stable performance upon cycling, retaining more than 80% of their initial capacity after 200 cycles at 1C rate. These results highlight the bright prospects of this material to meet the high energy density requirements for electric vehicles. 相似文献
20.
Li‐Ping Wang Tai‐Shan Wang Ya‐Xia Yin Ji‐Lei Shi Chun‐Ru Wang Yu‐Guo Guo 《Liver Transplantation》2019,9(28)
Solid‐state lithium metal batteries (SSLMBs) may become one of the high‐energy density storage devices for the next generation of electric vehicles. High safety and energy density can be achieved by utilizing solid electrolytes and Li metal anodes. Therefore, developing cathode materials which can match with Li metal anode efficiently is indispensable. In SSLMBs, Li metal anodes can afford the majority of active lithium ions, then lithium‐depleted cathode materials can be a competitive candidate to achieve high gravimetric energy density as well as save lithium resources. Li0.33MnO2 lithium‐depleted material is chosen, which also has the advantages of low synthesis temperature and low cost (cobalt‐free). Notably, solid‐state electrolyte can greatly alleviate the problem of manganese dissolution in the electrolyte, which is beneficial to improve the cycling stability of the battery. Thus, SSLMBs enable practical applications of lithium‐depleted cathode materials. 相似文献