Temperature effects on hard carbon derived from sawdust as anode materials for sodium ion batteries

Electrochemical energy storage devices, namely batteries, are vital in reducing greenhouse gas secretions and are reliable alternatives to fossil fuel-based electrical energy storage systems. Thus, hard carbon (HC) is one of the most promising sustainable materials in the energy storage sector. This study assembled sodium ion cells using sawdust powder resource-derived HC as an anode for sodium ion storage. We studied the effects of calcination temperature for the first time. Ball-milled and acid-washed sawdust powders were prepared by calcination at different temperatures. The characterization and electrochemical analyses of the HC synthesized at different temperatures were performed. We found that the ratios of C = O and the micro/meso pore size distributions in HCs corresponded highly to the sodium ion storage performance. The half-cell, HC1200 (at 1200 °C) exhibited the highest reversible capacity of 320 mAh/g after 200 cycles at 0.5 A/g. The Na3V2(PO4)3(NVP)//HC1200 pouch-type full cells showed superior capacity retention of 96.7% and a coulombic efficiency of 98.9% after 400 cycles. The as-synthesized biomass carbon derived from sawdust powder is a potential anode material for sodium ion batteries.