| 1 | Investigation the improvement of high voltage spinel LiNi_(0.5)Mn_(1.5)O_(4) cathode material by anneal process for lithium ion batteries显示文摘The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)has been attracted great attention as lithium ion cathode material due to its high voltage and large energy density.However,the practical application of LNMO is still limited by poor cycling stability.Herein,to improve the cycling stability of spinel LNMO,it was treated with anneal process at 900℃for 2 h after prepared by traditional solid-state method(LNMO-A).LNMO-A sample presented better electrochemical property especially under high rate,with capacity of 91.2 mAhg^(-1) after 1000 cycles under 10 C.Its superior electrochemical property was ascribed to the anneal process,resulting a stable crystal structure,indicated by XRD and Raman results of electrodes after 1000 cycles under 10 C and the longer solid-solution reaction,revealed by in-situ XRD.In addition,the optimized particle size,micro morphology and the larger BET area surface induced by the recrystallization in anneal process also contributes to its superior electrochemical property.What's more,the thin layer,which interacted LNMO-A particles with each other,induced by particles remelting in anneal process is also beneficial for its excellent electrochemical property.This study not only improved the electrochemical properties by anneal process,but also revealed the origins and mechanisms for its improvement. | Chao Gao Haiping Liu Sifu Bi Huilin Li Chengshuai Ma | 2021 | Green Energy & Environment2021，6，1： | 2 |
| 2 | Insight into the effect of graphene coating on cycling stability of LiNi_(0.5)Mn_(1.5)O_(4):Integration of structure-stability and surface-stability显示文摘Graphene has presented promising features for application in lithium ion batteries(LIBs)due to its superior electronic conductivity and high surface area.It has been successfully used for modifying cathode materials to meet the increasing demand for LIBs with longer cycle life.However,the improving effect of graphene on cycling stability is still unclear,which restricts its further application in LIBs.Herein,graphene coated hollow sphere-like structure LiNi0.5Mn1.5O4(LNMO)wasdesigned and the improvement mechanism of graphene coating on LNMO’s cycling stability was investigated.The results show that graphene coating not only contributes to suppress structural deformation from mechanistic reaction and extend solid-solution reaction,but also helps protect electrode from corrosion by the products from electrolyte decomposition and suppress the generation of surface defects,especially at high temperature.Owing to graphene coating,graphene coated LNMO can deliver a discharge capacity of 91 mAh g1 with high capacity retention of 82.5%after 1000 cycles under 20C and 83.8 mAh g1 with 94.5%capacity retention after 100 cycles under 2C at 55C.This work deeply explores the effect of graphene coating on cycling stability from crystal stability and surface stability,which will help a wider application of graphene in energy storage field. | Chao Gao Haiping Liu Sifu Bi Shanshan Fan Xiaohuan Meng Qiuying Li Chongxiao Luo | 2020 | Journal of Materiomics2020，6，4： | 1 |
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