Zhao Jian, Zhang Yuxiao, Zhuang Zechao, Deng Yating, Gao Ge, Li Jiayi, Meng Alan, Li Guicun, Wang Lei, Li Zhenjiang, Wang Dingsheng
College of Materials Science and Engineering College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, 266042, P. R. China.
Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
Angew Chem Int Ed Engl. 2024 Aug 12;63(33):e202404968. doi: 10.1002/anie.202404968. Epub 2024 Jul 18.
The heteroatom substitution is considered as a promising strategy for boosting the redox kinetics of transition metal compounds in hybrid supercapacitors (HSCs) although the dissimilar metal identification and essential mechanism that dominate the kinetics remain unclear. It is presented that d-p orbital hybridization between the metal and electrolyte ions can be utilized as a descriptor for understanding the redox kinetics. Herein, a series of Co, Fe and Cu heteroatoms are respectively introduced into NiSe cathodes, among them, only the moderate Co-substituted NiSe can hold the optimal d-p orbital hybridization resulted from the formed more unoccupied antibonding states π*. It inevitably enhances the interfacial charge transfer and ensures the balanced OH adsorption-desorption to accelerate the redox kinetics validated by the lowest reaction barrier (0.59 eV, matching well with the theoretical calculations). Coupling with the lower OH diffusion energy barrier, the prepared cathode delivers ultrahigh rate capability (~68.7 % capacity retention even the current density increases by 200 times), and an assembled HSC also presents high energy/power density. This work establishes the principles for determining heteroatoms and deciphers the underlying effects of the heteroatom substitution on improving redox kinetics and the rate performance of battery-type electrodes from a novel perspective of orbital-scale manipulation.
杂原子取代被认为是提高混合超级电容器（HSC）中过渡金属化合物氧化还原动力学的一种有前景的策略，尽管主导动力学的不同金属识别和基本机制仍不清楚。研究表明，金属与电解质离子之间的d-p轨道杂化可作为理解氧化还原动力学的一个描述符。在此，一系列钴、铁和铜杂原子分别被引入到NiSe阴极中，其中，只有适度的钴取代NiSe能够保持由形成的更多未占据反键态π*导致的最佳d-p轨道杂化。这不可避免地增强了界面电荷转移，并确保了平衡的OH吸附-解吸，以加速由最低反应势垒（0.59 eV，与理论计算结果吻合良好）验证的氧化还原动力学。结合较低的OH扩散能垒，制备的阴极具有超高的倍率性能（即使电流密度增加200倍，容量保持率仍约为68.7%），并且组装的HSC也具有高能量/功率密度。这项工作确立了确定杂原子的原则，并从轨道尺度操纵的新视角破译了杂原子取代对改善氧化还原动力学和电池型电极倍率性能的潜在影响。
