Zhang Jicheng, Zhang Qinghua, Wong Deniz, Zhang Nian, Ren Guoxi, Gu Lin, Schulz Christian, He Lunhua, Yu Yang, Liu Xiangfeng
Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, P. R. China.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, P. R. China.
Nat Commun. 2021 May 24;12(1):3071. doi: 10.1038/s41467-021-23365-9.
Oxygen release and irreversible cation migration are the main causes of voltage fade in Li-rich transition metal oxide cathode. But their correlation is not very clear and voltage decay is still a bottleneck. Herein, we modulate the oxygen anionic redox chemistry by constructing LiZrO slabs into LiMnO domain in LiNiMnO, which induces the lattice strain, tunes the chemical environment for redox-active oxygen and enlarges the gap between metallic and anionic bands. This modulation expands the region in which lattice oxygen contributes capacity by oxidation to oxygen holes and relieves the charge transfer from anionic band to antibonding metal-oxygen band under a deep delithiation. This restrains cation reduction, metal-oxygen bond fracture, and the formation of localized O molecule, which fundamentally inhibits lattice oxygen escape and cation migration. The modulated cathode demonstrates a low voltage decay rate (0.45 millivolt per cycle) and a long cyclic stability.
氧释放和不可逆的阳离子迁移是富锂过渡金属氧化物阴极电压衰减的主要原因。但它们之间的相关性尚不清楚，电压衰减仍然是一个瓶颈。在此，我们通过在LiNiMnO中将LiZrO板构建到LiMnO域中来调节氧阴离子氧化还原化学，这会引起晶格应变，调整氧化还原活性氧的化学环境，并扩大金属带和阴离子带之间的间隙。这种调节扩展了晶格氧通过氧化形成氧空穴来贡献容量的区域，并减轻了深度脱锂下从阴离子带到反键金属-氧带的电荷转移。这抑制了阳离子还原、金属-氧键断裂以及局部O分子的形成，从根本上抑制了晶格氧逸出和阳离子迁移。经过调制的阴极表现出低电压衰减率（每循环0.45毫伏）和长循环稳定性。
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