Zhu Shifan, Tao Haijun, Liu Yuxin, Ma Xiaoshuang, Wang Kunyan, Wang Yuqiao
Research Center for Nano Photoelectrochemistry and Devices, School of Chemistry and Chemical Engineering, Southeast University, Nanjing211189, China.
Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing211100, China.
J Phys Chem B. 2022 Dec 29;126(51):10913-10921. doi: 10.1021/acs.jpcb.2c06784. Epub 2022 Dec 18.
The electrolyte ion diffusion kinetics have an important impact on electrochemical energy storage. Herein, we report the effect of the intrinsic porosity of NiCoP on accelerating electrolyte ion diffusion kinetics and accommodating volume expansion during the charge/discharge process. The pore distribution model of electrode/electrolyte was designed and optimized by the finite element simulation, demonstrating the visualization and quantitative analysis of the diffusion process of the electrode/electrolyte interface with intrinsic porous structure. When the pore area ratio reached 50.01%, the theoretical diffusion coefficient of 1.41 × 10 m s would be conducive to the rapid diffusion of electrolytes. The electrode gained a specific capacity of 2805 F g at a current density of 1 A g based on the measured diffusion coefficient (1.79 × 10 m s), superior to 1.44-times that of the pristine electrode. The diffusion barriers of intrinsic porous NiCoP (3.19 eV) and conventional NiCoP (47.10 eV) were calculated by the density functional theory calculations, respectively. The intrinsic porous NiCoP was prepared by the hydrothermal treatment, annealing, and phosphating processes. The pore distribution was regulated by the concentration of NaHCO as a pore-forming additive. This work combines simulations and experiments to form a method to optimize diffusion kinetics at the electrode/electrolyte interface.
电解质离子扩散动力学对电化学储能有着重要影响。在此，我们报道了NiCoP的本征孔隙率对加速电解质离子扩散动力学以及在充放电过程中容纳体积膨胀的影响。通过有限元模拟设计并优化了电极/电解质的孔隙分布模型，展示了具有本征多孔结构的电极/电解质界面扩散过程的可视化和定量分析。当孔隙面积比达到50.01%时，理论扩散系数为1.41×10 m s将有利于电解质的快速扩散。基于测得的扩散系数（1.79×10 m s），该电极在电流密度为1 A g时获得了2805 F g的比容量，优于原始电极的1.44倍。分别通过密度泛函理论计算得出本征多孔NiCoP（3.19 eV）和传统NiCoP（47.10 eV）的扩散势垒。本征多孔NiCoP通过水热处理、退火和磷化工艺制备。通过作为造孔添加剂的NaHCO浓度来调节孔隙分布。这项工作将模拟和实验相结合，形成了一种优化电极/电解质界面扩散动力学的方法。
