Transition metal oxides with layered structure have been widely used as cathode materials for lithium-ion batteries(LIBs)which have relatively high energy density,large capacity and long life.However,in the long-term ...Transition metal oxides with layered structure have been widely used as cathode materials for lithium-ion batteries(LIBs)which have relatively high energy density,large capacity and long life.However,in the long-term electrochemical cycle,the inevitable degradation of performance of LIBs due to structural degradation in cathodes severely restricts their large-scale practical applications.Understanding the underlying mechanism of structural degradation is the most critical scientific problem.Recently,in situ transmission electron microscopy(TEM)has become a useful tool to study the structural and compositional evolutions at atomic scale in electrochemical reactions,which provided a unique and in-depth understanding of the structural degradation.In this review,we discuss the recent advances in the in situ TEM,focusing on its role in revealing the structural degradation mechanisms in the four key places:(1)the interface between the cathodes and electrolyte;(2)the cathode surface;(3)the particle interior and(4)those induced by thermal effect.The insight gained by the in-situ TEM which is still developing at its fast pace is unique and expected to provide guidance for designing better layered cathode materials.展开更多
Developing efficient platinum-based electrocatalysts with super durability for the oxygen reduction reaction(ORR)is highly desirable to promote the large-scale commercialization of fuel cells.Although progress has bee...Developing efficient platinum-based electrocatalysts with super durability for the oxygen reduction reaction(ORR)is highly desirable to promote the large-scale commercialization of fuel cells.Although progress has been made in this aspect,the electrochemical kinetics and stability of platinum-based catalysts are still far from the requirements of the practical applications.Herein,PtPdFeCoNi high-entropy alloy(HEA)nanoparticles were demonstrated via a high-temperature injection method.PtPdFeCoNi HEA nanocatalyst exhibits outstanding catalytic activity and stability towards ORR due to the high entropy,lattice distortion,and sluggish diffusion effects of HEA,and the HEA nanoparticles delivered a mass activity of 1.23 A/mgPt and a specific activity of 1.80 mA/cmPt 2,which enhanced by 6.2 and 4.9 times,respectively,compared with the values of the commercial Pt/C catalyst.More importantly,the high durability of PtPdFeCoNi HEA/C was evidenced by only 6 mV negativeshifted half-wave potential after 50,000 cycles of accelerated durability test(ADT).展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52127816,520722825 and 2022072)the Hubei Provincial Natural Science Foundation of China(Distinguished Young Scholars,No.2022CFA042)the In-dependent Innovation Projects of the Hubei Longzhong Laboratory(No.2022ZZ-10).
文摘Transition metal oxides with layered structure have been widely used as cathode materials for lithium-ion batteries(LIBs)which have relatively high energy density,large capacity and long life.However,in the long-term electrochemical cycle,the inevitable degradation of performance of LIBs due to structural degradation in cathodes severely restricts their large-scale practical applications.Understanding the underlying mechanism of structural degradation is the most critical scientific problem.Recently,in situ transmission electron microscopy(TEM)has become a useful tool to study the structural and compositional evolutions at atomic scale in electrochemical reactions,which provided a unique and in-depth understanding of the structural degradation.In this review,we discuss the recent advances in the in situ TEM,focusing on its role in revealing the structural degradation mechanisms in the four key places:(1)the interface between the cathodes and electrolyte;(2)the cathode surface;(3)the particle interior and(4)those induced by thermal effect.The insight gained by the in-situ TEM which is still developing at its fast pace is unique and expected to provide guidance for designing better layered cathode materials.
基金the National Natural Science Foundation of China(Nos.21972016 and 21773023)National Youth Top-notch Talent Support Program of China,Sichuan Science and Technology Program(No.2020YJ0243)+1 种基金Jiangsu Province Cultivation base for State Key Laboratory of Photovoltaic Science and Technology(No.SKLPST 202103)Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(No.2022-K28).
文摘Developing efficient platinum-based electrocatalysts with super durability for the oxygen reduction reaction(ORR)is highly desirable to promote the large-scale commercialization of fuel cells.Although progress has been made in this aspect,the electrochemical kinetics and stability of platinum-based catalysts are still far from the requirements of the practical applications.Herein,PtPdFeCoNi high-entropy alloy(HEA)nanoparticles were demonstrated via a high-temperature injection method.PtPdFeCoNi HEA nanocatalyst exhibits outstanding catalytic activity and stability towards ORR due to the high entropy,lattice distortion,and sluggish diffusion effects of HEA,and the HEA nanoparticles delivered a mass activity of 1.23 A/mgPt and a specific activity of 1.80 mA/cmPt 2,which enhanced by 6.2 and 4.9 times,respectively,compared with the values of the commercial Pt/C catalyst.More importantly,the high durability of PtPdFeCoNi HEA/C was evidenced by only 6 mV negativeshifted half-wave potential after 50,000 cycles of accelerated durability test(ADT).
基金financially supported by the National Key Research and Development Program of China (2018YFB0703600)the National Natural Science Foundation of China (51772232)+1 种基金the 111 Project of China (B07040)Wuhan Frontier Project on Applied Research Foundation (2019010701011405)
