高镍三元正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)在高压下的研究进展

Advancements in the modification of high-voltage Ni-rich ternary cathode material LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)for lithium-ion batteries

随着科技的发展和时代进步,能源消耗日益增大,新能源的开发利用已成为迫在眉睫的问题。锂离子电池因具有高的能量密度、长的循环寿命和宽的工作温度范围等优点,在过去的几十年里,得到了快速发展。高镍三元正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)因具有高能量密度和低成本的优点,被认为是下一代锂离子电池中最具发展潜力的正极材料之一。目前NCM811的充电截止电压限制在4.3V,进一步提升充电截止电压可以提高电极材料的能量密度,然而在高充电截止电压情况下,由于NCM811存在阳离子混排、裂纹的产生和扩展、晶格氧的析出、与电解液接触而产生副反应和晶格畸变等因素使得材料的结构稳定性下降和不可逆相变的产生,导致其严重的容量衰减和循环性能的急剧下降,阻碍了NCM811在高压条件下的大规模应用。本文综述了高压下NCM811改性策略的最新研究进展,首先阐述了高压条件下NCM811的失效机理,然后介绍了元素掺杂、表面包覆、复合改性策略对其电化学性能的影响规律及其改善机理。最后展望了NCM811改善策略的发展方向,并针对不同改性策略提出了面向实际应用的可行性方案。

With the increasing global demand for energy,the development and utilization of new energy sources have become pressing challenges.To address energy concerns,lithium-ion batteries have seen rapid advancements over the past few decades and are now widely used in electronic devices and vehicle power supplies.The high-nickel ternary cathode material LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is considered one of the most promising cathode materials for next-generation lithium-ion batteries due to its high energy density and cost-effectiveness.Increasing the operating voltage can significantly enhance the energy density of this electrode material.However,under high voltage,the structural stability of NCM811 is compromised due to issues such as cation mixing,crack formation and propagation,lattice oxygen release,side reactions,and lattice distortion caused by electrolyte contact.These factors lead to irreversible phase transitions,severe capacity degradation,and a sharp decline in cycling performance,hindering the large-scale application of high-voltage NCM811.This paper reviews the latest research on modification strategies for NCM811 under high voltage.It begins with an overview of the failure mechanisms of NCM811 at high voltage,followed by a discussion on how element doping,surface coating,and composite modification strategies impact its electrochemical performance and the mechanisms by which these modifications improve stability.Finally,the paper explores future directions for NCM811 improvement strategies,proposing feasible,application-oriented solutions for various modification approaches.