通过Mo掺杂诱导低Li/Ni混排程度增强Li1.2Ni0.13Fe0.13Mn0.54O2 可逆容量与循环稳定性
Enhancing reversible capacity and cycling stability of Li1.2Ni0.13Fe0.13Mn0.54O2 by inducing low Li/Ni misalignment through Mo doping
冉沛林 1吴康 2赵恩岳 3王芳卫 2毋志民4
作者信息
- 1. 重庆师范大学物理与电子工程学院,重庆 401331;松山湖材料实验室,东莞 523808;中国科学院物理研究所,北京凝聚态物理国家研究中心,北京 100190
- 2. 松山湖材料实验室,东莞 523808;中国科学院物理研究所,北京凝聚态物理国家研究中心,北京 100190
- 3. 松山湖材料实验室,东莞 523808
- 4. 重庆师范大学物理与电子工程学院,重庆 401331
- 折叠
摘要
富锂层状氧化物因能量密度高和成本低,有望成为下一代锂离子电池正极的重要候选材料.然而,富锂正极材料中阴离子氧化还原反应使晶格氧不稳定,导致电压衰减和不可逆容量损失.尽管铁代无钴富锂材料可以实现较少的电压衰减,但存在严重的阳离子混排和较差的动力学.采用一种简单易行的高价离子掺杂策略,在Li1.2Ni0.13Fe0.13Mn0.54O2(LNFMO)中掺入Mo元素,拓宽了锂层间距,为Li+的传输提供了更宽的通道,改善了Li+的扩散动力学,有效抑制了阳离子混排,进一步稳定了层状结构.得益于此,Mo掺杂后的富锂材料表现出显著增强的电化学性能,在 0.2 C电流密度下表现出 209.48 mAh/g的初始放电比容量.1 C下的初始放电比容量从 137.02 mAh/g提高到 165.15 mAh/g;循环 300次后,仍有 117.49 mAh/g的放电比容量,电压衰减由 2.09 mV/cycle降低为 1.66 mV/cycle.本文对Mo掺杂后的正极材料进行了系统表征并揭示了循环稳定的机理,为高性能富锂正极材料的设计提供了重要参考.
Abstract
Li-ion batteries(LIBs)are widely used in mobile devices and electric vehicles,but the traditional layered transition metal cathode material,LiTMO2(TM=Ni,Co,Mn,or Al),has a low energy density that cannot satisfy the demand of commercial applications.The Li-rich Mn-based layered oxides(LRLOs)are a strong competitor to the traditional layered cathode materials for their specific capacity of more than 200 mAh/g.Due to the high energy density and low cost,Li-rich Mn-based layered oxides(LRLO)have been a promising candidate cathode for next-generation Li-ion batteries.The anionic redox reaction(ARR)in LRLO destabilizes the lattice oxygen,leading to voltage degradation and capacity loss.Although iron-substituted cobalt-free Li-rich materials can achieve less voltage decay,they suffer severe cation disorder and poor kinetics.Here,we develop a simple and feasible high-valent ion doping strategy by doping Mo into Li1.2Ni0.13Fe0.13Mn0.54O2(LNFMO),which expands the Li layer spacing and provides a broader channel for Li+ transport,thereby improving the diffusion kinetics of Li+,effectively suppressing the cation disorder,and further stabilizing the layered structure.As a result,the Mo-doped LRLO exhibits significantly enhanced electrochemical performance,with an initial reversible capacity of 209.48 mAh/g at 0.2 C,and the initial specific capacity increasing from 137.02 mAh/g to 165.15 mAh/g at 1 C.After 300 cycles,specific capacity remains 117.49 mAh/g for the Mo-doped cathode,and the voltage decay decreases from 2.09 mV/cycle to 1.66 mV/cycle.The Mo-doped LRLO is systematically characterized,and the mechanism of cycle stabilization is revealed,which provides an important reference for designing high performance Li-rich cathode.
关键词
锂离子电池/富锂层状氧化物/正极材料/阳离子混排Key words
Li-ion batteries/Li-rich layered oxides/cathode materials/cationic disorder引用本文复制引用
基金项目
重庆市教委科学技术研究计划重点项目(KJZD-K202300512)
国家自然科学基金(52088101)
国家自然科学基金(12105197)
出版年
2024
国家科技期刊平台
NSTL
万方数据