Reinvented sodium anode by creating a metal-bulk storage matrix with an expanded 3D plating/stripping mechanism.

Abstract

Direct metal anodes are plating/stripping processes without a supporting framework and bulk ion conductivity; they are the electrodes susceptible to collapse and limiting the electrochemical reaction to the two-dimensional surface. The focus of this era is mostly on building a solid electrolyte interface (SEI). However, simply building protective layers cannot address essential issues; a thorough transformation of the metal electrode bulk is critical. We propose a reconstructed sodium metal anode (RSMA) by implanting an activatable ion-conductive network to the bulk. NaPF₆ will be activated with an electrolyte to conduct ions and form an anion-derived SEI. Conductive polymers become the supporting skeleton; thus, the RSMA has a metal-bulk storage matrix and an expanded three-dimensional plating/stripping mechanism and permits the homogeneous deposition/dissolution of Na⁺ in high dimensions. Last, RSMA symmetric cells were stably cycled for 2700 hours and achieved a 100% depth of discharge. RSMA||PB cells can achieve 10-coulomb cycling and a proof-of-concept pouch cell energy density of 367 watt-hours per kilogram.