Ultrafast synthesis of hard carbon anodes for sodium-ion batteries

Significance Hard carbon (HC) is one of the most promising anode materials for alkali metal-ion batteries, which is generally prepared by annealing in a tubular furnace with a low heating rate and long duration at a target temperature. Herein, we report an innovating sintering method to quickly fabricate HC even within one minute and ultrafast heating rate by multifield-regulated spark plasma sintering (SPS) technology. This is a universal way to the rapid preparation of various HCs from different carbon precursors. Notably, HCs prepared from SPS possess significantly lower oxygen contents and higher electronic conductivity than the traditional sintering way due to the remarkably accelerated pyrolysis reaction, leading to excellent electrochemical Na-ion storage performance.