Layered oxide cathode materials may undergo irreversible oxygen loss and severe phase transitions during high voltage cycling and may be susceptible to transition metal dissolution, adversely affecting their electrochemical performance. Here, to address these challenges, we propose synergistic doping of nonmetallic elements and in situ electrochemical diffusion as potential solution strategies. Among them, the distribution of the nonmetallic element fluorine within the material can be regulated by doping boron, thereby suppressing manganese dissolution through surface enrichment of fluorine. Furthermore, in situ electrochemical diffusion of fluorine from the surface into the bulk of the materials after charging reduces the energy barrier of potassium ion diffusion while effectively inhibiting irreversible oxygen loss under high voltage. The modified K_0.5Mn_0.83Mg_0.1Ti_0.05B_0.02F_0.1O_1.9 layered oxide cathode exhibits a high capacity of 147 mAh g^–1 at 50 mA g^–1 and a long cycle life of 2200 cycles at 500 mA g^–1. This work demonstrates the efficacy of synergistic doping and in situ electrochemical diffusion of nonmetallic elements and provides valuable insights for optimizing rechargeable battery materials.

中文翻译：

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钾层状氧化物阴极高压稳定性的合理调控


层状氧化物正极材料在高电压循环过程中可能会经历不可逆的氧损失和严重的相变，并且可能容易受到过渡金属溶解的影响，从而对其电化学性能产生不利影响。在这里，为了应对这些挑战，我们提出非金属元素的协同​​掺杂和原位电化学扩散作为潜在的解决策略。其中，可以通过掺杂硼来调节非金属元素氟在材料内的分布，从而通过氟的表面富集来抑制锰的溶解。此外，充电后氟从表面原位电化学扩散到材料本体中，降低了钾离子扩散的能垒，同时有效抑制高电压下不可逆的氧损失。改性K _0.5 Mn _0.83 Mg _0.1 Ti _0.05 B _0.02 F _0.1 O _1.9 层状氧化物正极在50 mA g ^–1 下表现出147 mAh g ^–1 的高容量和在500 mA g-1下2200次循环的长循环寿命< b9> 。这项工作展示了非金属元素协同掺杂和原位电化学扩散的功效，并为优化可充电电池材料提供了宝贵的见解。