掺杂-包覆改性单晶LiNi0.83Co0.12Mn0.05O2的制备技术及性能研究

Preparation technology and properties of modified single-crystalline LiNi0.83Co0.12Mn0.05O2 cathode materials by doping and coating

  • 摘要: 高镍三元正极材料以其能量密度高的特性成为目前动力型锂离子电池主流正极材料之一,但目前高镍三元材料存在循环稳定性较差、大倍率充放电性能较差等问题,限制了其规模化应用。三元材料的单晶化可以有效降低循环过程中的颗粒间微裂纹产生,结合表面包覆可有效提高高镍三元正极材料的循环稳定性。同时,高价阳离子掺杂可有效提高锂离子传输速率,提高高镍三元材料的倍率充放电性能。本文采用高温固相法制备W6+、Zr4+共掺杂和H3BO3、Al2O3双包覆的高镍单晶LiNi0.83Co0.12Mn0.05O2材料,并探究其电化学性能的变化。在3.0~4.3 V电压范围内,与未掺杂材料相比,W-Zr共掺杂的LiNi0.83Co0.12Mn0.05O2在不同放电倍率下具有更好的电化学性能;采用H3BO3和Al2O3表面双包覆的LiNi0.83Co0.12Mn0.05O2正极材料在1 C倍率下循环100圈后容量保持率为96.7%。

     

    Abstract: Ni-rich ternary positive materials have become one of the most preferred cathode materials for application in power lithium-ion batteries owing to their high energy density. However, these cathode materials suffer from inferior cycling performance and poor rate capability, seriously impeding their practical application to scale. The single crystallization of ternary materials can effectively mitigate the generation of particle cracking and improve the cycling stability of Ni-rich cathode materials. At the same time, high-valence cationic doping can effectively improve the transmission rate of lithium ions, and the charge-discharge performance of high-nickel ternary materials. In this paper, nickel-rich single crystal LiNi0.83Co0.12Mn0.05O2 materials doped with W6+ and Zr4+, combined with H3BO3 and Al2O3 double coating was prepared by high-temperature solid phase method, and their changes in electrochemical properties was explored. It is found that LiNi0.83Co0.12Mn0.05O2 doped with W-Zr displays better electrochemical performance compared with the un-doped cathode under the different magnifications specific discharge capacity in 3.0-4.3 V. The capacity retention rate of LiNi0.83Co0.12Mn0.05O2 materials with H3BO3 and Al2O3 double coating was 96.7% after 100 cycles at 1.0 C.

     

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