Integrating Lithiophilic Gradient Structure with Nano-Ionic Channel Network to Regulate Li Distribution for Dendrite-Free Lithium Metal Anode.

3D Li hosts with lithiophilic gradient structure are extensively explored to mitigate Li dendrite formation by promoting bottom-up Li plating and reducing local current density. However, the absence of well-defined nano-ionic channels in these designs limits their ability to regulate Li distribution, leading to uncontrolled Li dendrite growth under high current densities and large areal capacities. Herein, this study presents a novel graphene-based 3D Li host that integrates nano-ionic channel network into a lithiophilic gradient structure, denoted as IC-GGLH. The IC-GGLH features a lithiophilic gradient structure with nano-sized SnO particles well-dispersed within a graphene-CNT mixture at the bottom layer, acting as Li nucleation seeds, while a lithiophobic CNT top layer serves as a protective barrier. Additionally, abundant nano-pores are generated at the SnO-graphene interface during air heat treatment via a catalytic carbon gasification process, effectively functioning as nano-ionic channels to enhance Li transport and distribution. This synergistic design enhances Li transport and ensures uniform Li plating across the entire IC-GGLH, as verified by various electrochemical analysis and ex situ SEM. Consequently, the IC-GGLH electrode demonstrates remarkable cycling stability in half cells, symmetric cells, and full cells, maintaining low voltage polarization.