Interpenetrated Structures for Enhancing Ion Diffusion Kinetics in Electrochemical Energy Storage DevicesOACSTPCDEI

The architectural design of electrodes offers new opportunities for next-generation electrochemical energy storage devices(EESDs)by increasing surface area,thickness,and active materials mass loading while maintaining good ion diffusion through optimized electrode tor-tuosity.However,conventional thick electrodes increase ion diffusion length and cause larger ion concentration gradients,limiting reaction kinetics.We demonstrate a strategy for building interpenetrated structures that shortens ion diffusion length and reduces ion concentration inho-mogeneity.This free-standing device structure also avoids short-circuiting without needing a separator.The feature size and number of interpenetrated units can be adjusted during printing to balance surface area and ion diffusion.Starting with a 3D-printed interpenetrated polymer substrate,we metallize it to make it conductive.This substrate has two individually addressable electrodes,allowing selective electro-deposition of energy storage materials.Using a Zn//MnO2 battery as a model system,the interpenetrated device outperforms conventional separate electrode configurations,improving volumetric energy density by 221％ and exhibiting a higher capacity retention rate of 49％compared to 35％at temperatures from 20 to 0 ℃.Our study introduces a new EESD architecture applicable to Li-ion,Na-ion batteries,supercapacitors,etc.