High-pressure-assisted discovery of porous carbon frameworks from NaC6 for high-performance sodium-ion battery anodes

Abstract

Designing high-performance anode materials with rapid Na-ion transport, high capacity, and structural stability remains a major challenge for sodium-ion batteries (SIBs). In this study, we introduce a high-pressure-assisted structural design strategy in which sodium serves as a chemical template to direct the formation of the carbon framework. Global structure prediction at 30 GPa revealed two low-energy NaC6 phases—Na-bct-C12 and Na-IGN—which, upon sodium removal, were converted into porous carbon frameworks. The resulting bct-C12 and interlocked graphene network (IGN) structures demonstrated excellent dynamical and thermal stability, along with metallic or topological semimetal electronic properties. They exhibited outstanding sodium storage performance, delivering a theoretical capacity of 372 mAh/g, ultra-fast Na+ diffusion with coefficients of up to 3.75 × 10−4 cm2/s, and minimal volume expansion (<7%) during sodiation. This study highlights that pressure-assisted templating can facilitate the discovery of metastable yet functionally superior porous carbon phases, offering a robust platform for the rational design of high-rate SIB anodes.