Hard Carbon Anodes: Fundamental Understanding and Commercial Perspectives for Na‐Ion Batteries beyond Li‐Ion and K‐Ion Counterparts

TLDR

Hard carbon is a promising anode for alkali‑metal ion batteries, especially sodium‑ion batteries, due to its outstanding electrochemical performance. The review aims to interpret the challenges and opportunities of hard‑carbon anodes and outline future research and commercialization directions. It examines ion‑storage mechanisms, material design, electrolyte optimization, SEI behavior, Coulombic efficiency, safety, all‑climate performance, and commercial prototypes of sodium‑ion batteries based on hard carbon.

Abstract

Abstract Hard carbon (HC) is recognized as a promising anode material with outstanding electrochemical performance for alkali metal‐ion batteries including lithium‐ion batteries (LIBs), as well as their analogs sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs). Herein, a comprehensive review of the recent research is presented to interpret the challenges and opportunities for the applications of HC anodes. The ion storage mechanisms, materials design, and electrolyte optimizations for alkali metal‐ion batteries are illustrated in‐depth. HC is particularly promising as an anode material for SIBs. The solid‐electrolyte interphase, initial Coulombic efficiency, safety concerns, and all‐climate performances, which are vital for practical applications, are comprehensively discussed. Furthermore, commercial prototypes of SIBs based on HC anodes are extensively elaborated. The remaining challenges and research perspectives are provided, aiming to shed light on future research and early commercialization of HC‐based SIBs.