Shan Hui, Qin Jian, Wang Jingjing, Sari Hirbod Maleki Kheimeh, Lei Li, Xiao Wei, Li Wenbin, Xie Chong, Yang Huijuan, Luo Yangyang, Zhang Gaini, Li Xifei
Shaanxi international Joint Research Center of Surface Technology for Energy Storage Materials, Institute of Advanced Electrochemical Energy and School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China.
Adv Sci (Weinh). 2022 Jun;9(18):e2200341. doi: 10.1002/advs.202200341. Epub 2022 Apr 25.
Heteroatom doping effectively tunes the electronic conductivity of transition metal selenides (TMSs) with rapid K accessibility in potassium ion batteries (PIBs). Although considerable efforts are dedicated to investigating the relationship between the doping strategy and the resulting electrochemistry, the doping mechanisms, especially in view of the ion and electronic diffusion kinetics upon cycling, are seldom elucidated systematically. Herein, the crystal structure stability, charge/ion state, and bandgap of the active materials are found to be precisely modulated by favorable heteroatom doping, resulting in intrinsically fast kinetics of the electrode materials. Based on the combined mechanisms of intercalation and conversion reactions, electron and K ion transfer in Ni-doped CoSe embedded in carbon nanocomposites (Ni-CoSe @NC) can be significantly enhanced via electronic engineering. Benefiting from the synthetic controlled Ni grains, the heterointerface formed by the intermediate products of electrochemical reactions in Ni-CoSe @NC strengthens the conversion kinetics and interdiffusion process, developing a low-barrier mesophase with optimized potassium storage. Overall, an electronic tuning strategy can offer deeper atomic insights into the conversion reaction of TMSs in PIBs.
杂原子掺杂有效地调节了过渡金属硒化物（TMSs）的电子导电性，使其在钾离子电池（PIBs）中具有快速的钾离子可达性。尽管人们致力于研究掺杂策略与由此产生的电化学之间的关系，但掺杂机制，尤其是从循环过程中的离子和电子扩散动力学角度来看，很少得到系统的阐明。在此，发现通过有利的杂原子掺杂可以精确调节活性材料的晶体结构稳定性、电荷/离子状态和带隙，从而使电极材料具有内在的快速动力学。基于嵌入碳纳米复合材料（Ni-CoSe@NC）中的Ni掺杂CoSe的嵌入和转化反应的综合机制，通过电子工程可以显著增强电子和钾离子的转移。受益于合成控制的Ni晶粒，Ni-CoSe@NC中电化学反应中间产物形成的异质界面增强了转化动力学和互扩散过程，形成了具有优化钾存储性能的低势垒中间相。总体而言，电子调谐策略可以为PIBs中TMSs的转化反应提供更深入的原子层面见解。
