The development of high-performance and low-cost cathode materials is of great significance for the progress in lithium-ion batteries.The use of Co and even Ni is not conducive to the sustainable and healthy developme...The development of high-performance and low-cost cathode materials is of great significance for the progress in lithium-ion batteries.The use of Co and even Ni is not conducive to the sustainable and healthy development of the power battery industry owing to their high cost and limited resources.Here,we report LiMn_(2)O_(4)integrated with coating and doping by Sn self-segregation.Auger electron energy spectrum and soft X-ray absorption spectrum show that the coating is Sn-rich LiMn_(2)O_(4),with a small Sn doping in the bulk phase.The integration strategy can not only mitigate the Jahn–Teller distortion but also effectively avoid the dissolution of manganese.The as-obtained product demonstrates superior high initial capacities of 124 mAh·g^(-1)and 120 mAh·g^(-1)with the capacity retention of 91.1%and 90.2%at 25℃and55℃after 50 cycles,respectively.This novel material-processing method highlights a new development direction for the progress of cathode materials for lithium-ion batteries.展开更多
LiF-coated LiMn2O4 samples were prepared via a chemical method. X-ray diffraction(XRD) patterns show that the bare LiMn2O4 and the LiF-coated LiMn2O4 samples are all spinel structure in Fd 3mspace group. The apparent ...LiF-coated LiMn2O4 samples were prepared via a chemical method. X-ray diffraction(XRD) patterns show that the bare LiMn2O4 and the LiF-coated LiMn2O4 samples are all spinel structure in Fd 3mspace group. The apparent morphologies,the spectroscopic properties and the LiF distributions of the as-prepared samples were studied by scanning electronic microscopy(SEM),Fourier infrared spectroscopy(FTIR),transmission electronic microscopy(TEM),selected area electron diffractometry(SAED) respectively. The LiF-coated LiMn2O4 gets a more stable surface than bare LiMn2O4,and changes the interaction between the cathode material and the electrolyte. Therefore,it can endure overcharge in the secondary lithium batteries,and achieve better electrochemical performances even when charged to 4.7 V and 4.9 V.展开更多
Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and ...Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and charge-discharge test in this paper. The results show that a good clad coated on parent material can be synthesized by the sol-gel method, and the materials with modification have perfect spinel structure. LiCo0.09Mn1.91O3.92F0.08 materials coated by LiCoO2 improve the stability of crystal structure and decrease the dissolution of Mn into electrolyte. With the LiCoO2 content increasing, the specific capacity and cycle performance of samples are improved. The capacity loss is also suppressed distinctly even at 55 ℃.展开更多
基金supported by the International Science&Technology Cooperation of China(No.2019YFE0100200)the National Natural Science Foundation of China(No.53130202)the Basic Research Program of Shanxi Province,China(No.20210302123259)。
文摘The development of high-performance and low-cost cathode materials is of great significance for the progress in lithium-ion batteries.The use of Co and even Ni is not conducive to the sustainable and healthy development of the power battery industry owing to their high cost and limited resources.Here,we report LiMn_(2)O_(4)integrated with coating and doping by Sn self-segregation.Auger electron energy spectrum and soft X-ray absorption spectrum show that the coating is Sn-rich LiMn_(2)O_(4),with a small Sn doping in the bulk phase.The integration strategy can not only mitigate the Jahn–Teller distortion but also effectively avoid the dissolution of manganese.The as-obtained product demonstrates superior high initial capacities of 124 mAh·g^(-1)and 120 mAh·g^(-1)with the capacity retention of 91.1%and 90.2%at 25℃and55℃after 50 cycles,respectively.This novel material-processing method highlights a new development direction for the progress of cathode materials for lithium-ion batteries.
基金Project (2002CB211800) supported by the National Basic Research Program of Chinaproject (000Y05-21) supported by the Excellent Young Scholar Research Fund of Beijing Institute of Technologyproject (20060542012) supported by the Teaching and Research Fund of Beijing Institute of Technology
文摘LiF-coated LiMn2O4 samples were prepared via a chemical method. X-ray diffraction(XRD) patterns show that the bare LiMn2O4 and the LiF-coated LiMn2O4 samples are all spinel structure in Fd 3mspace group. The apparent morphologies,the spectroscopic properties and the LiF distributions of the as-prepared samples were studied by scanning electronic microscopy(SEM),Fourier infrared spectroscopy(FTIR),transmission electronic microscopy(TEM),selected area electron diffractometry(SAED) respectively. The LiF-coated LiMn2O4 gets a more stable surface than bare LiMn2O4,and changes the interaction between the cathode material and the electrolyte. Therefore,it can endure overcharge in the secondary lithium batteries,and achieve better electrochemical performances even when charged to 4.7 V and 4.9 V.
文摘Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and charge-discharge test in this paper. The results show that a good clad coated on parent material can be synthesized by the sol-gel method, and the materials with modification have perfect spinel structure. LiCo0.09Mn1.91O3.92F0.08 materials coated by LiCoO2 improve the stability of crystal structure and decrease the dissolution of Mn into electrolyte. With the LiCoO2 content increasing, the specific capacity and cycle performance of samples are improved. The capacity loss is also suppressed distinctly even at 55 ℃.
