He Wei, Ye Fangjun, Lin Jie, Wang Qian, Xie Qingshui, Pei Fei, Zhang Chenying, Liu Pengfei, Li Xiuwan, Wang Laisen, Qu Baihua, Peng Dong-Liang
State Key Lab of Physical Chemistry of Solid Surface, Collaborative Innovation Center of Chemistry for Energy Materials, College of Materials and Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China.
Shenzhen Research Institute of Xiamen University, Shenzhen, 518000, People's Republic of China.
Nanomicro Lett. 2021 Oct 11;13(1):205. doi: 10.1007/s40820-021-00725-0.
There are plenty of issues need to be solved before the practical application of Li- and Mn-rich cathodes, including the detrimental voltage decay and mediocre rate capability, etc. Element doping can effectively solve the above problems, but cause the loss of capacity. The introduction of appropriate defects can compensate the capacity loss; however, it will lead to structural mismatch and stress accumulation. Herein, a three-in-one method that combines cation-polyanion co-doping, defect construction, and stress engineering is proposed. The co-doped Na/SO can stabilize the layer framework and enhance the capacity and voltage stability. The induced defects would activate more reaction sites and promote the electrochemical performance. Meanwhile, the unique alternately distributed defect bands and crystal bands structure can alleviate the stress accumulation caused by changes of cell parameters upon cycling. Consequently, the modified sample retains a capacity of 273 mAh g with a high-capacity retention of 94.1% after 100 cycles at 0.2 C, and 152 mAh g after 1000 cycles at 2 C, the corresponding voltage attenuation is less than 0.907 mV per cycle.
在富锂锰基正极材料实际应用之前，还有许多问题需要解决，包括有害的电压衰减和一般的倍率性能等。元素掺杂可以有效解决上述问题，但会导致容量损失。引入适当的缺陷可以弥补容量损失；然而，这会导致结构失配和应力积累。在此，提出了一种将阳离子-阴离子共掺杂、缺陷构建和应力工程相结合的三合一方法。共掺杂的Na/SO可以稳定层状结构并提高容量和电压稳定性。诱导产生的缺陷会激活更多的反应位点并促进电化学性能。同时，独特的交替分布的缺陷带和晶带结构可以缓解循环过程中由于电池参数变化引起的应力积累。因此，改性后的样品在0.2 C下循环100次后保持273 mAh g的容量，高容量保持率为94.1%，在2 C下循环1000次后为152 mAh g，相应的电压衰减小于每循环0.907 mV。
