摘要
Spin regulation of active sites is sparking much interest in boosting oxygen electrocatalytic performance.However,in amorphous electrocatalysts,the design principle of spin regulation to promote catalytic activity remains unclear.Herein,we synthesized a series of heteroatom-doped amorphous transition metal sulfides with regulated spin states using a one-step hydrothermal process.Especially in Modoped CoS,the spin state of Co^(2+)was successfully modulated to the low-spin state,which could optimize the adsorption free energy of various intermediates,improving the oxygen reduction reaction kinetics.The fabricated Zn-air batteries(ZABs)delivered good cycle stability(over 100 h).The large ZAB(100 cm^(2))exhibited a high discharge voltage(1.25 V under 0.5 A)and a superior overall mass-energy density(93 W h kg^(−1)),which illuminated a 2.5-m light-emitting-diode ribbon for over seven days.This work provides new insight into the mechanism of engineering spin states in amorphous materials for oxygen electrocatalysis.
调控活性位点的自旋态是提高氧电催化性能的重要研究方向.然而,在非晶电催化剂中,提升催化活性的自旋调控机制尚不清楚.本工作通过一步水热法合成了一系列杂原子掺杂的非晶态过渡金属硫化物材料,其中在钼(Mo)掺杂的硫化钴(CoS)中,部分Co^(2+)的电子构型由高自旋态HS(t_(2g)^(5)e_(g)^(2))转变为低自旋态LS(t_(2g)^(6)e_(g)^(1)),优化了各种中间体的吸附自由能,从而加速了氧化还原反应动力学.以Mo-CoS为阴极催化剂组装的锌-空气电池具有优异的循环稳定性(超过100 h).大模具锌空气电池(100 cm^(2))在大电流(0.5 A)下仍表现出高放电电压(1.25 V)和高质量能量密度(93 W h kg^(−1)),可以点亮2.5 m的发光二极管条带持续7天以上.这项工作为理解非晶材料中自旋态调控对氧电催化活性影响的机理提供了借鉴.
基金
the National Natural Science Foundation of China(52122107 and 972224)
the Postdoctoral International Exchange Program(YJ20200139).
