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1.
Dongsheng Geng Ning Ding T. S. Andy Hor Sheau Wei Chien Zhaolin Liu Delvin Wuu Xueliang Sun Yun Zong 《Liver Transplantation》2016,6(9)
Lithium ‐ air batteries have become a focus of research on future battery technologies. Technical issues associated with lithium‐air batteries, however, are rather complex. Apart from the sluggish oxygen reaction kinetics which demand efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts, issues are also inherited from the nature of an open battery system and the use of reactive metal lithium as anode. Lithium‐air batteries, which exchange oxygen directly with ambient air, face more challenges due to the additional oxidative agents of moisture, carbon dioxide, etc. which degrade the metal lithium anode, deteriorating the performance of the batteries. In order to improve the cycling performance one must hold a full picture of lithium‐oxygen electrochemistry in the presence of carbon dioxide and/or moisture and fully understand the fundamentals of chemistry reactions therein. Recent advances in the exploration of the effect of moisture and CO2 contaminants on Li‐O2 batteries are reviewed, and the mechanistic understanding of discharge/charge process in O2 at controlled level of moisture and/or CO2 are illustrated. Prospects for development opportunities of Li‐air batteries, insight into future research directions, and guidelines for the further development of rechargeable Li‐air batteries are also given. 相似文献
2.
Atomic Modulation of FeCo–Nitrogen–Carbon Bifunctional Oxygen Electrodes for Rechargeable and Flexible All‐Solid‐State Zinc–Air Battery
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Chang‐Yuan Su Hui Cheng Wei Li Zhao‐Qing Liu Nan Li Zhufeng Hou Fu‐Quan Bai Hong‐Xing Zhang Tian‐Yi Ma 《Liver Transplantation》2017,7(13)
Rational design and exploration of robust and low‐cost bifunctional oxygen reduction/evolution electrocatalysts are greatly desired for metal–air batteries. Herein, a novel high‐performance oxygen electrode catalyst is developed based on bimetal FeCo nanoparticles encapsulated in in situ grown nitrogen‐doped graphitic carbon nanotubes with bamboo‐like structure. The obtained catalyst exhibits a positive half‐wave potential of 0.92 V (vs the reversible hydrogen electrode, RHE) for oxygen reduction reaction, and a low operating potential of 1.73 V to achieve a 10 mA cm?2 current density for oxygen evolution reaction. The reversible oxygen electrode index is 0.81 V, surpassing that of most highly active bifunctional catalysts reported to date. By combining experimental and simulation studies, a strong synergetic coupling between FeCo alloy and N‐doped carbon nanotubes is proposed in producing a favorable local coordination environment and electronic structure, which affords the pyridinic N‐rich catalyst surface promoting the reversible oxygen reactions. Impressively, the assembled zinc–air batteries using liquid electrolytes and the all‐solid‐state batteries with the synthesized bifunctional catalyst as the air electrode demonstrate superior charging–discharging performance, long lifetime, and high flexibility, holding great potential in practical implementation of new‐generation powerful rechargeable batteries with portable or even wearable characteristic. 相似文献
3.
The increasing demand for portable and wearable electronics requires lightweight, thin, and highly flexible power sources, for example, flexible zinc‐air batteries (ZABs). The so‐far reported flexible ZAB devices mostly remain bulky, with a design consisting of two relatively thick substrates (e.g., carbon cloths and/or metal foams) and a gel electrolyte‐coated separator in between. Herein, an ultrathin (≈0.2 mm) solid‐state ZAB with high flexibility and performance is introduced by directly forming self‐standing active layers on each surface of an alkaline polymer membrane through an ink‐casting/hot‐pressing approach. A Fe/N‐doped 3D carbon with hierarchic pores and an interconnected network structure is used as cathode electrocatalyst, so that the backing gas‐diffusion layer (e.g., carbon cloth) can be abandoned. What is further, a microstructure‐modulating method to significantly increase the FeN4 active sites for oxygen reduction reaction is developed, thus significantly boosting the performance of the ZAB. The assembled solid‐state ZAB manifests remarkable peak power density of 250 mW cm?3 and high capacity of 150.4 mAh cm?3 at 8.3 mA cm?3, as well as excellent flexibility. The new design should provide valuable opportunity to the portable and wearable electronics. 相似文献
4.
Enhanced Cyclability of Lithium–Oxygen Batteries with Electrodes Protected by Surface Films Induced via In Situ Electrochemical Process
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Bin Liu Wu Xu Jinhui Tao Pengfei Yan Jianming Zheng Mark H. Engelhard Dongping Lu Chongmin Wang Ji‐Guang Zhang 《Liver Transplantation》2018,8(11)
Although the rechargeable lithium–oxygen (Li–O2) batteries have extremely high theoretical specific energy, the practical application of these batteries is still limited by the instability of their carbon‐based air‐electrode, Li metal anode, and electrodes, toward reduced oxygen species. Here a simple one‐step in situ electrochemical precharging strategy is demonstrated to generate thin protective films on both carbon nanotubes (CNTs), air‐electrodes and Li metal anodes simultaneously under an inert atmosphere. Li–O2 cells after such pretreatment demonstrate significantly extended cycle life of 110 and 180 cycles under the capacity‐limited protocol of 1000 mA h g?1 and 500 mA h g?1, respectively, which is far more than those without pretreatment. The thin‐films formed from decomposition of electrolyte during in situ electrochemical precharging processes in an inert environment, can protect both CNTs air‐electrode and Li metal anode prior to conventional Li–O2 discharge/charge cycling, where reactive reduced oxygen species are formed. This work provides a new approach for protection of carbon‐based air‐electrodes and Li metal anodes in practical Li–O2 batteries, and may also be applied to other battery systems. 相似文献
5.
Novel Route to Fe‐Based Cathode as an Efficient Bifunctional Catalysts for Rechargeable Zn–Air Battery
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Efficient bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts are of great importance for rechargeable metal–air batteries. Herein, FeNx/C catalysts are synthesized by pyrolysis of thiourea and agarose containing α‐Fe2O3 nanoplate as Fe precursor, where α‐Fe2O3 nanoplate can prevent the aggregation of carbon sheets to effectively improve the specific surface area during the carbonization process. The FeNx/C‐700‐20 catalyst displays excellent catalytic performance for both ORR and OER activity in alkaline conditions with more positive onset potential (1.1 V vs the reversible hydrogen electrode) and half‐wave potential, higher stability, and stronger methanol tolerance in alkaline solution, which are all superior to that of the commercial Pt/C catalyst. In this study, the detailed analyses demonstrate that the coexistence of Fe‐based species and high content of Fe‐Nx both play an important role for the catalytic activity. Furthermore, FeNx/C‐700‐20 as cathode catalyst in Zn–air battery possesses higher charge–discharge stability and power density compared with that of commercial Pt/C catalyst, displaying great potential in practical implementation of for the rechargeable energy devices. 相似文献
6.
Karolina Kordek Lixue Jiang Kaicai Fan Zhengju Zhu Li Xu Mohammad Al‐Mamun Yuhai Dou Shan Chen Porun Liu Huajie Yin Piotr Rutkowski Huijun Zhao 《Liver Transplantation》2019,9(4)
A flexible air electrode (FAE) with both high oxygen electrocatalytic activity and excellent flexibility is the key to the performance of various flexible devices, such as Zn–air batteries. A facile two‐step method, mild acid oxidation followed by air calcination that directly activates commercial carbon cloth (CC) to generate uniform nanoporous and super hydrophilic surface structures with optimized oxygen‐rich functional groups and an enhanced surface area, is presented here. Impressively, this two‐step activated CC (CC‐AC) exhibits superior oxygen electrocatalytic activity and durability, outperforming the oxygen‐doped carbon materials reported to date. Especially, CC‐AC delivers an oxygen evolution reaction (OER) overpotential of 360 mV at 10 mA cm?2 in 1 m KOH, which is among the best performances of metal‐free OER electrocatalysts. The practical application of CC‐AC is presented via its use as an FAE in a flexible rechargeable Zn–air battery. The bendable battery achieves a high open circuit voltage of 1.37 V, a remarkable peak power density of 52.3 mW cm?3 at 77.5 mA cm?3, good cycling performance with a small charge–discharge voltage gap of 0.98 V and high flexibility. This study provides a new approach to the design and construction of high‐performance self‐supported metal‐free electrodes. 相似文献
7.
Chuanlong Wang Huan Wang Xiaofei Hu Edward Matios Jianmin Luo Yiwen Zhang Xuan Lu Weiyang Li 《Liver Transplantation》2019,9(5)
Room‐temperature (RT) sodium–sulfur (Na–S) batteries are attractive cost‐effective platforms as the next‐generation energy storage systems by using all earth‐abundant resources as electrode materials. However, the slow kinetics of Na–S chemistry makes it hard to achieve high‐rate performance. Herein, a facile and scalable approach has been developed to synthesize hollow sodium sulfide (Na2S) nanospheres embedded in a highly hierarchical and spongy conductive carbon matrix, forming an intriguing architecture similar to the morphology of frogspawn coral, which has shown great potential as a cathode for high‐rate performance RT Na–S batteries. The shortened Na‐ion diffusion pathway benefits from the hollow structures together with the fast electron transfer from the carbon matrix contributes to high electrochemical reactivity, leading to superior electrochemical performance at various current rates. At high current densities of 1.4 and 2.1 A g?1, high initial discharge capacities of 980 and 790 mAh g?1sulfur can be achieved, respectively, with reversible capacities stabilized at 600 and 400 mAh g?1sulfur after 100 cycles. As a proof of concept, a Na‐metal‐free Na–S battery is demonstrated by pairing the hollow Na2S cathode with tin‐based anode. This work provides guidance on rational materials design towards the success of RT high‐rate Na–S batteries. 相似文献
8.
Xixi Wang Jaka Sunarso Qian Lu Ziling Zhou Jie Dai Daqin Guan Wei Zhou Zongping Shao 《Liver Transplantation》2020,10(5)
Constructing highly active electrocatalysts with superior stability at low cost is a must, and vital for the large‐scale application of rechargeable Zn–air batteries. Herein, a series of bifunctional composites with excellent electrochemical activity and durability based on platinum with the perovskite Sr(Co0.8Fe0.2)0.95P0.05O3?δ (SCFP) are synthesized via a facile but effective strategy. The optimal sample Pt‐SCFP/C‐12 exhibits outstanding bifunctional activity for the oxygen reduction reaction and oxygen evolution reaction with a potential difference of 0.73 V. Remarkably, the Zn–air battery based on this catalyst shows an initial discharge and charge potential of 1.25 and 2.02 V at 5 mA cm?2, accompanied by an excellent cycling stability. X‐ray photoelectron spectroscopy, X‐ray absorption near‐edge structure, and extended X‐ray absorption fine structure experiments demonstrate that the superior performance is due to the strong electronic interaction between Pt and SCFP that arises as a result of the rapid electron transfer via the Pt? O? Co bonds as well as the higher concentration of surface oxygen vacancies. Meanwhile, the spillover effect between Pt and SCFP also can increase more active sites via lowering energy barrier and change the rate‐determining step on the catalysts surface. Undoubtedly, this work provides an efficient approach for developing low‐cost and highly active catalysts for wider application of electrochemical energy devices. 相似文献
9.
Rational design and construction of a multifunctional electrocatalyst featuring with high efficiency and low cost is fundamentally important to realize new energy technologies. Herein, a trifunctional electrocatalyst composed of FePx nanoparticles and Fe–N–C moiety supported on the N‐, P‐codoped carbon (NPC) is masterly synthesized by a facile one‐pot pyrolysis of the mixture of tannic acid, ferrous chloride, and sodium hydrogen phosphate. The synergy of each component in the FePx/Fe–N–C/NPC catalyst renders high catalytic activities and excellent durability toward both oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The electrocatalytic performance and practicability of the robust FePx/Fe–N–C/NPC catalyst are further investigated under the practical operation conditions. Particularly, the overall water splitting cell assembled by the FePx/Fe–N–C/NPC catalyst only requires a voltage of 1.58 V to output the benchmark current density of 10 mA cm?2, which is superior to that of IrO2–Pt/C‐based cell. Moreover, the FePx/Fe–N–C/NPC‐based zinc–air batteries deliver high round‐trip efficiency and remarkable cycling stability, much better than that of Pt/C–IrO2 pair‐based batteries. This work offers a new strategy to design and synthesize highly effective multifunctional electrocatalysts using cheaper tannic acid derived carbon as support applied in electrochemical energy devices. 相似文献
10.
Gwang‐Hee Lee Seun Lee Jae‐Chan Kim Dong Wook Kim Yongku Kang Dong‐Wan Kim 《Liver Transplantation》2017,7(6)
Lithium‐oxygen batteries represent a significant scientific challenge for high‐rate and long‐term cycling using oxygen electrodes that contain efficient electrocatalysts. The mixed transition metal oxide catalysts provide the most efficient catalytic activity for partial heterogeneous surface cations with oxygen vacancies as the active phase. They include multiple oxidation states and oxygen vacancies. Here, using a combination of transmission electron microscopy, differential electrochemical mass spectrometry, X‐ray photoelectron spectroscopy, and electrochemical properties to probe the surface of the MnMoO4 nanowires, it is shown that the intrinsic MnMoO4 oxygen vacancies on the oxygen electrode are an effective strategy to achieve a high reversibility and high efficiency for lithium‐oxygen (Li‐O2) batteries. The modified MnMoO4 nanowires exhibit a highly stable capacity at a fixed capacity of 5000 mA h gsp?1 (calculated weight of Super P carbon black) during 50 cycles, a high‐rate capability at a current rate of 3000 mA gsp?1 during 70 cycles, and a long‐term reversible capacity during 188 cycles at a fixed capacity of 1000 mA h gsp?1. It is demonstrated that this strategy for creating mixed transition metal oxides (e.g., MnMoO4) may pave the way for the new structural design of electrocatalysts for Li‐O2 batteries. 相似文献
11.
12.
To develop high‐power and high‐energy batteries with a long life remains a great challenge, even combining the benefits of metal (fast kinetics and high capacity) and carbon materials (robust structure). Among them, Al‐ion batteries based on aluminum anode and graphite carbon cathode have gained lots of interests as one of the most promising technologies. Here, it is demonstrated that the size of graphitic material in ab plane and c direction plays an important role in anion intercalation chemistry. Sharply decreasing the size of vertical dimension (c direction) strongly facilitates the kinetics and charge transfer of anions (de)intercalation. On the other hand, increasing the size of horizontal dimension (ab plane) contributes to improving the flexibility of graphitic materials, which results in raising the cycling stability. Meanwhile, chloroaluminate anions are reversibly intercalated into the interlayer of graphite materials, leading to the staging behaviors. In the end, an ultrafast Al‐ion battery with exceptional long life is achieved based on large‐sized few‐layer graphene as a cathode and aluminum metal as an anode. 相似文献
13.
Tiva Sharifi Eduardo Gracia‐Espino Anran Chen Guangzhi Hu Thomas Wgberg 《Liver Transplantation》2020,10(11)
The oxygen reduction reaction (ORR) is of great importance in energy‐converting processes such as fuel cells and in metal–air batteries and is vital to facilitate the transition toward a nonfossil dependent society. The ORR has been associated with expensive noble metal catalysts that facilitate the O2 adsorption, dissociation, and subsequent electron transfer. Single‐ or few‐atom motifs based on earth‐abundant transition metals, such as Fe, Co, and Mo, combined with nonmetallic elements, such as P, S, and N, embedded in a carbon‐based matrix represent one of the most promising alternatives. Often these are referred to as single atom catalysts; however, the coordination number of the metal atom as well as the type and nearest neighbor configuration has a strong influence on the function of the active sites, and a more adequate term to describe them is metal‐coordinated motifs. Despite intense research, their function and catalytic mechanism still puzzle researchers. They are not molecular systems with discrete energy states; neither can they fully be described by theories that are adapted for heterogeneous bulk catalysts. Here, recent results on single‐ and few‐atom electrocatalyst motifs are reviewed with an emphasis on reports discussing the function and the mechanism of the active sites. 相似文献
14.
Electronic and Defective Engineering of Electrospun CaMnO3 Nanotubes for Enhanced Oxygen Electrocatalysis in Rechargeable Zinc–Air Batteries
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Shengjie Peng Xiaopeng Han Linlin Li Shulei Chou Dongxiao Ji Huangjiao Huang Yonghua Du Jian Liu Seeram Ramakrishna 《Liver Transplantation》2018,8(22)
Rational design and massive production of bifunctional catalysts with superior oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities are essential for developing metal–air batteries and fuel cells. Herein, controllable large‐scale synthesis of sulfur‐doped CaMnO3 nanotubes is demonstrated via an electrospinning technique followed by calcination and sulfurization treatment. The sulfur doping can not only replace oxygen atoms to increase intrinsic electrical conductivity but also introduce abundant oxygen vacancies to provide enough catalytically active sites, which is further demonstrated by density functional theory calculation. The resulting sulfur‐modified CaMnO3 (CMO/S) exhibits better electrocatalytic activity for ORR and OER in alkaline solution with higher stability performance than the pristine CMO. These results highlight the importance of sulfur treatment as a facile yet effective strategy to improve the ORR and OER catalytic activity of the pristine CaMnO3. As a proof‐of‐concept, a rechargeable Zn–air battery using the bifunctional catalyst exhibits a small charge–discharge voltage polarization, and long cycling life. Furthermore, a solid‐state flexible and rechargeable Zn–air battery gives superior discharge–charge performance and remarkable stability. Therefore, the CMO/S nanotubes might be a promising replacement to the Pt‐based electrocatalysts for metal–air batteries and fuel cells. 相似文献
15.
Dinh Chuong Nguyen Duy Thanh Tran Thi Luu Luyen Doan Do Hwan Kim Nam Hoon Kim Joong Hee Lee 《Liver Transplantation》2020,10(8)
A novel hybrid of small core@shell structured CoSx@Cu2MoS4 uniformly hybridizing with a molybdenum dichalcogenide/N,S‐codoped graphene hetero‐network (CoSx@Cu2MoS4‐MoS2/NSG) is prepared by a facile route. It shows excellent performance toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in alkaline medium. The hybrid exhibits rapid kinetics for ORR with high electron transfer number of ≈3.97 and exciting durability superior to commercial Pt/C. It also demonstrates great potential with remarkable stability for HER and OER, requiring low overpotential of 118.1 and 351.4 mV, respectively, to reach a current density of 10 mA cm?2. An electrolyzer based on CoSx@Cu2MoS4‐MoS2/NSG produces low cell voltage of 1.60 V and long‐term stability, surpassing a device of Pt/C + RuO2/C. In addition, a Zn‐air battery using cathodic CoSx@Cu2MoS4‐MoS2/NSG catalyst delivers a high cell voltage of ≈1.44 V and a power density of 40 mW cm?2 at 58 mA cm?2, better than the state‐of‐the‐art Pt/C catalyst. These achievements are due to the rational combination of highly active core@shell CoSx@Cu2MoS4 with large‐area and high‐porosity MoS2/NSG to produce unique physicochemical properties with multi‐integrated active centers and synergistic effects. The outperformances of such catalyst suggest an advanced candidate for multielectrocatalysis applications in metal‐air batteries and hydrogen production. 相似文献
16.
Jianwen Liang Xiaona Li Yang Zhao Lyudmila V. Goncharova Weihan Li Keegan R. Adair Mohammad Norouzi Banis Yongfeng Hu Tsun‐Kong Sham Huan Huang Li Zhang Shangqian Zhao Shigang Lu Ruying Li Xueliang Sun 《Liver Transplantation》2019,9(38)
Li metal is a promising anode material for all‐solid‐state batteries, owing to its high specific capacity and low electrochemical potential. However, direct contact of Li metal with most solid‐state electrolytes induces severe side reactions that can lead to dendrite formation and short circuits. Moreover, Li metal is unstable when exposed to air, leading to stringent processing requirements. Herein, it is reported that the Li3PS4/Li interface in all‐solid‐state batteries can be stabilized by an air‐stable LixSiSy protection layer that is formed in situ on the surface of Li metal through a solution‐based method. Highly stable Li cycling for over 2000 h in symmetrical cells and a lifetime of over 100 cycles can be achieved for an all‐solid‐state LiCoO2/Li3PS4/Li cell. Synchrotron‐based high energy X‐ray photoelectron spectroscopy in‐depth analysis demonstrates the distribution of different components within the protection layer. The in situ formation of an electronically insulating LixSiSy protection layer with highly ionic conductivity provides an effective way to prevent Li dendrite formation in high‐energy all‐solid‐state Li metal batteries. 相似文献
17.
Carbon‐supported single atomic metals (SAMs) have aroused great interest in energy conversion and storage fields. However, metal content has to date, been far below expectation. Additionally, theoretical calculations show that SAMs are superb anchoring sites for alkali metal‐ion storage, but the experimental research remains untouched. Herein, a metal–organophosphine framework derived strategy is proposed to prepare carbon microcuboids‐supported single atomic Cu with a high content of 26.3 wt%. Atomic Cu is stabilized mainly by P moieties, exhibiting robust stability even in concentrated HCl and HNO3. Interestingly, experimental investigations and first‐principle calculations indicate that Cu atoms can alter the Na storage behavior and enable Na to maintain an ionic state at a fully discharging state for sodium‐ion batteries, which may be a new pathway to mitigate safety concerns of dendrite formation. The Cu atoms also enhance electron transfer and diffusion kinetics. As a result, the carbon cuboids can deliver a high capacity of 107.7 mAh g?1 at 5 A g?1 and show a long life of 1000 cycles for Na storage. This strategy offers a new possibility for fabricating high‐content P‐coordinated atomic metals for energy conversion and storage. 相似文献
18.
Highly Active and Stable Graphene Tubes Decorated with FeCoNi Alloy Nanoparticles via a Template‐Free Graphitization for Bifunctional Oxygen Reduction and Evolution
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Shiva Gupta Liang Qiao Shuai Zhao Hui Xu Ye Lin Surya V. Devaguptapu Xianliang Wang Mark T. Swihart Gang Wu 《Liver Transplantation》2016,6(22)
Development of highly active and stable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts from earth‐abundant elements remains a grand challenge for highly demanded reversible fuel cells and metal–air batteries. Carbon catalysts have many advantages over others due to their low cost, excellent electrical conductivity, high surface area, and easy functionalization. However, they typically cannot withstand the highly oxidative OER environment. Here, a new class of bifunctional electrocatalyst is reported, consisting of ultralarge sized nitrogen doped graphene tubes (N‐GTs) (>500 nm) decorated with FeCoNi alloy particles. These tubes are prepared from an inexpensive precursor, dicyandiamide, via a template‐free graphitization process. The ORR/OER activity and the stability of these graphene tube catalysts depend strongly on the transition metal precursors. The best performing FeCoNi‐derived N‐GT catalyst exhibits excellent ORR and OER activity along with adequate electrochemical durability over a wide potential window (0–1.9 V) in alkaline media. The measured OER current is solely due to desirable O2 evolution, rather than carbon oxidation. Extensive electrochemical and physical characterization indicated that high graphitization degree, thicker tube walls, proper nitrogen doping, and presence of FeCoNi alloy particles are vital for high bifunctional activity and electrochemical durability of tubular carbon catalysts. 相似文献
19.
Jin Goo Lee Jae‐Ha Myung Aaron B. Naden Ok Sung Jeon Yong Gun Shul John T. S. Irvine 《Liver Transplantation》2020,10(10)
For efficient catalysis and electrocatalysis well‐designed, high‐surface‐area support architectures covered with highly dispersed metal nanoparticles with good catalyst‐support interactions are required. In situ grown Ni nanoparticles on perovskites have been recently reported to enhance catalytic activities in high‐temperature systems such as solid oxide cells (SOCs). However, the micrometer‐scale primary particles prepared by conventional solid‐state reactions have limited surface area and tend to retain much of the active catalytic element within the bulk, limiting efficacy of such exsolution processes in low‐temperature systems. Here, a new, highly efficient, solvothermal route is demonstrated to exsolution from smaller scale primary particles. Furthermore, unlike previous reports of B‐site exsolution, it seems that the metal nanoparticles are exsolved from the A‐site of these perovskites. The catalysts show large active site areas and strong metal‐support interaction (SMSI), leading to ≈26% higher geometric activity (25 times higher mass activity with 1.4 V of Eon‐set) and stability for oxygen‐evolution reaction (OER) with only 0.72 µg base metal contents compared to typical 20 wt% Ni/C and even commercial 20 wt% Ir/C. The findings obtained here demonstrate the potential design and development of heterogeneous catalysts in various low‐temperature electrochemical systems including alkaline fuel cells and metal–air batteries. 相似文献
20.
Trinary Layered Double Hydroxides as High‐Performance Bifunctional Materials for Oxygen Electrocatalysis
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Li Qian Zhiyi Lu Tianhao Xu Xiaochao Wu Yang Tian Yaping Li Ziyang Huo Xiaoming Sun Xue Duan 《Liver Transplantation》2015,5(13)
Layered double hydroxides (LDHs) are a family of high‐profile layer materials with tunable metal species and interlayer spacing, and herein the LDHs are first investigated as bifunctional electrocatalysts. It is found that trinary LDH containing nickel, cobalt, and iron (NiCoFe‐LDH) shows a reasonable bifunctional performance, while exploiting a preoxidation treatment can significantly enhance both oxygen reduction reaction and oxygen evolution reaction activity. This phenomenon is attributed to the partial conversion of Co2+ to Co3+ state in the preoxidation step, which stimulates the charge transfer to the catalyst surface. The practical application of the optimized material is demonstrated with a small potential hysteresis (800 mV for a reversible current density of 20 mA cm?2) as well as a high stability, exceeding the performances of noble metal catalysts (commercial Pt/C and Ir/C). The combination of the electrochemical metrics and the facile and cost‐effective synthesis endows the trinary LDH as a promising bifunctional catalyst for a variety of applications, such as next‐generation regenerative fuel cells or metal–air batteries. 相似文献