Lithium-rich layered cathode materials recently arouse highly attention for the high discharge capacities over conventional cathode materials, but trapped for severe voltage decay, poor cycling stability and inferior rate performance upon cycling. In this work, introducing Cs ions into the Li layer is employed to prepare Cs⁺-doped cathode material Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ via a simple sol-gel method and a subsequent calcination process. The Cs⁺ − doped sample exhibits much enhanced electrochemical performances in comparison with that of pristine sample, especially the rate capability (171.1 mAh g⁻¹ compared to 150.2 mAh g⁻¹ at 5C). Meanwhile, the Cs-doped one reaches an initial discharge capacity of 247.4 mAh g⁻¹ with improved initial Coulombic efficiency of 86.0% at 0.2C rate and outruns for 177.9 mAh g⁻¹ of discharge capacity after 100 cycles at 0.5C. Additionally, it is observed that the Cs⁺- doped sample has a well-defined layered structure and an expanded Li slab space caused by the Cs⁺ accommodation, which provides facile Li⁺ diffusion paths and reduces the energy barrier of the Li⁺ insertion/extraction in the crystal lattice. More importantly, the Cs doping is in favor of stabilizing the crystal structure and meanwhile restraining the decrease of discharge voltage by alleviating the phase transition of layered to spinel structure upon cycling, thus greatly contributing to the better electrochemical performances.

最近，富含锂的分层阴极材料因其比常规阴极材料的高放电容量而引起了高度关注，但由于严重的电压衰减，较差的循环稳定性和循环时的差速性能而陷入困境。在这项工作中，通过将Cs离子引入Li层中，通过简单的溶胶-凝胶法和随后的煅烧过程来制备Cs ⁺掺杂的正极材料Li _1.2 Mn _0.54 Ni _0.13 Co _0.13 O ₂。与原始样品相比，掺杂Cs ⁺ -的样品表现出大大增强的电化学性能，特别是速率能力（171.1 mAh g ^-1与150.2 mAh g在5C时为^-1）。同时，掺有Cs的Cs初始放电容量为247.4 mAh g ^-1，在0.2C速率下初始库仑效率提高了86.0％，在0.5C循环100次后，放电容量超过了177.9 mAh g ^-1。此外，可以观察到，掺杂Cs ^+的样品具有明确的分层结构，并且由于Cs ⁺调节而导致Li平板空间扩大，从而提供了便捷的Li ⁺扩散路径并降低了Li ⁺的能垒。晶格中的插入/提取。更重要的是，Cs掺杂有利于稳定晶体结构，同时通过减轻循环时层状结构向尖晶石结构的相变而抑制放电电压的降低，从而极大地改善了电化学性能。