Zr浓度梯度掺杂改性NCM811高镍三元正极材料的研究
Study on Zr Concentration Gradient Doping Modified NCM811 High-nickel Ternary Cathode Materials
张圆雪 1牟粤 1文越华 1李萌 1王跃 1朱振威 1孟闻捷1
作者信息
- 1. 军事科学院防化研究院 总体研究所,北京 100191
- 折叠
摘要
高镍三元电极材料是高比能量锂离子电池最具应用前景的正极材料,但随着镍含量增大,其结构稳定性变差.为此,本文制备了Zr浓度梯度掺杂改性的NCM811(Zr-PCG)高镍三元正极材料,探究了Zr掺杂量对材料结构、形貌、元素分布、电化学性能的影响及其机制,以改善其结构稳定性和循环性能.结果表明,Zr掺杂由内向外呈渐进式梯度设计,高结合能的Zr—O键可有效抑制游离氧的析出,掺杂量为1%的1.0 Zr-PCG电极材料晶体结构稳定性最优,同时Zr掺杂也显著提高了电极的热稳定性.1.0 Zr-PCG 电极在 1C 下的初始放电比容量达到193.1 mAh/g,循环200 次后,容量保持率为近90%,明显高于未掺杂NCM811 电极的容量保持率(82.4%);充放电倍率增至10C,1.0 Zr-PCG电极仍可放出152.7 mAh/g的容量,表现出优异的倍率性能.
Abstract
Ni-rich layered lithium transition-metal oxides,LiNi1-x Mx O2(M = transition metal)electrode materials are the most promising high-energy cathode materials for lithium-ion batteries,but their structural stability declines with nickel content increasing.Therefore,in this paper,the NCM811 high-nickel ternary anode material(Zr-PCG)was prepared by concentration gradient Zr doping modification,and the influence of Zr doping amount on the material structure,morphology,element distribution,and electrochemical performance was deeply investigated with the view of im-proving its structural stability and cycling performance.The results show that the Zr doping is de-signed in a gradual gradient from the centre to the outer layer of each particle.The high binding en-ergy of Zr—O bonds can effectively suppress the escape of free oxygen.The 1.0 Zr PCG cathode with a doping amount of 1%has a crystal structure with the best stability,and the Zr doping also significantly elevates the thermal stability of NCM811 electrodes.The 1.0 Zr PCG cathode delivers an initial discharge capacity of 193.1 mAh/g at 1C,and exhibits the capacity retention of nearly 90%after 200 cycles,which is substantially higher than that of the undoped NCM811 cathode(82.4%).When the current rate is increased to 10C,the 1.0 Zr PCG electrode can still release a capacity of 152.7 mAh/g,demonstrating its excellent rate performance.
关键词
高比能量/锂离子电池/高镍三元正极/Zr掺杂/梯度掺杂Key words
high energy density/lithium-ion batteries/high-nickel ternary anode/Zr doping/gra-dient doping引用本文复制引用
基金项目
国家自然科学基金面上项目(21975284)
出版年
2024
NETL
NSTL
万方数据