Progress of high energy density cathode materials for lthium-ion batteries
Lithium-ion batteries stand out from other secondary batteries due to their advantages of high operating voltage,high energy density,and long cycle life,and are used in all aspects of our lives.And the growing demand for clean and sustainable energy to replace traditional fossil fuels has driven the development of secondary batteries on a different level.However,even successfully commercialized lithium-ion batteries still face significant challenges in cost and safety,thus researchers are eager to find solutions to battery materials with higher energy density and better safety.Therefore,in-depth understanding of the multi-scale structure in the electrode materials and its evolution mechanism during the electrochemical reaction processes,is crucial for the design and optimization of high-capacity electrode materials,which is also conducive to the overall battery performance.Lithium-ion batteries are often named after the category of cathode materials,which reflects the importance of the cathode materials.Transition metal oxide cathode materials are a very important class of cathode materials,as they dominate the majority of the market in consumer electronics,transportation and electrochemical energy storage due to their broad compositions and structures.Among them,the lithium cobalt oxide(LiCoO2)cathode,is widely used for consumer electronics and vehicles.From a materials perspective,layered transition metal oxides have higher theoretical capacity,high operating voltage,and low manufacturing cost.However,their application potential has not yet been fully realized due to electrochemical stability issues.Here,we review some representative cathode materials for lithium-ion batteries,of particular interest we discussed the development and structural properties of lithium cobalt oxides,focused on their working principle and failure mechanism,the corresponding modification strategies in enhancing electrochemical stability are summarized and analyzed.The expanding demand for higher energy density urges us to increase the cut-off voltage of the cathodes.However,the practical application of LiCoO2 at 4.6 V suffers from the devastating Hl-3 metastable phase transition,severe interfacial side reactions due to aggressive oxygen species and cobalt loss,as well as thermal run-away in LiCoO2.Based on this,we focus on the fundamental structural understanding of LiCoO2 cathodes from long-term studies.Multi-scale structures concerning LiCoO2 bulk and surfaces and various structural issues along with their origins and corresponding stabilization strategies with specific mechanisms are uncovered and elucidated at length,which will certainly deepen and advance our knowledge of LiCoO2 structures,and further their inherent relationship with electrochemical performance.And on the grounds of these understandings,remaining questions and opportunities for future stabilization of LiCoO2 structures are also emphasized;at the same time,the engineering application status and improvement measures of lithium-ion battery cathode materials are introduced,laying the foundation for the innovation of the next generation batteries.Finally,the development prospects of high energy density rechargeable batteries are prospected.
lithium-ion batteryhigh energy density cathode materialslithium cobalt oxideworking principlefailure mechanismmodification method
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维普
