LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)@Cr_(2)O_(5)composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr_(2)O_(5),playing a synergistic role in improving the cyclic stability,...LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)@Cr_(2)O_(5)composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr_(2)O_(5),playing a synergistic role in improving the cyclic stability,initial discharge capacity and the security of low cut-off voltage(2.0 V).When the mass ratio of Cr_(2)O_(5)in NCA is 45%(mass),the capacity retention rate increases from 58.5% without Cr_(2)O_(5)to 69.3% in the range of 2.0-4.3 V.The initial discharge capacity of NCA@Cr_(2)O_(5)composite material is 211.4 mA·h·g^(-1),its first coulombic efficiency is 94.2%,and the charging capacity remains approximately constant when mixed with 15%(mass)Cr_(2)O_(5).The reason for the improvement of the initial charge-discharge efficiency(ICDE)was explained.Impedance and cyclic voltammetry analysis reveal more detailed reasons of the observed improvements.Compared with NCA cathode material,the NCA@Cr_(2)O_(5)composite material can provide not only additional stable sites and channels for Li^(+)insertion/extraction to make up for the loss of active Li^(+)sites and prevent the accumulation of Li+in the circulation process,but also protect the NCA electrode from the corrosion of the electrolyte decomposition by the Cr_(2)O_(5)nanoparticles adhering to NCA interface.展开更多
基金financially supported by the National Natural Science Foundation of China (52064031)the Program for Innovative Research Team in the University of Ministry of Education of China (IRT_17R48)National Natural Science Foundation of China (51674129)
文摘LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)@Cr_(2)O_(5)composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr_(2)O_(5),playing a synergistic role in improving the cyclic stability,initial discharge capacity and the security of low cut-off voltage(2.0 V).When the mass ratio of Cr_(2)O_(5)in NCA is 45%(mass),the capacity retention rate increases from 58.5% without Cr_(2)O_(5)to 69.3% in the range of 2.0-4.3 V.The initial discharge capacity of NCA@Cr_(2)O_(5)composite material is 211.4 mA·h·g^(-1),its first coulombic efficiency is 94.2%,and the charging capacity remains approximately constant when mixed with 15%(mass)Cr_(2)O_(5).The reason for the improvement of the initial charge-discharge efficiency(ICDE)was explained.Impedance and cyclic voltammetry analysis reveal more detailed reasons of the observed improvements.Compared with NCA cathode material,the NCA@Cr_(2)O_(5)composite material can provide not only additional stable sites and channels for Li^(+)insertion/extraction to make up for the loss of active Li^(+)sites and prevent the accumulation of Li+in the circulation process,but also protect the NCA electrode from the corrosion of the electrolyte decomposition by the Cr_(2)O_(5)nanoparticles adhering to NCA interface.
