Synthesis of the electrochemically stable sulfur-doped bamboo charcoal as the anode material of potassium-ion batteries

As an emerging energy storage technology, potassium-ion batteries (KIBs) are suitable for large-scale energy storage applications due to their abundant resources and low cost, but the known anode materials generally exhibit poor electrochemical performance. In this paper, synthesis of sulfur-doped bamboo charcoal (S-BC) anode materials are carried out to match the intercalation/deintercalation cycles of K+ by using biomass bamboo as a precursor and sulfur as a modifying element. Benefiting from the unique structure and composition formed during the activation, carbonization, and subsequently vulcanization at 700 °C, the S-BC materials exhibit stabilized electrochemical performance. The optimized S-BC-1 anode delivers a high specific capacity of 339.3 mAh g−1 at 50 mA g−1, a rate capacity of 124.2 mAh g−1 at 1 A g−1, and a cycling retention of 203.8 mAh g−1 at 200 mA g−1 after 300 cycles. It is indicated that the residual oxygen atoms and the doping sulfur in the BS can provide more active sites and increase the conductivity. The sustainable bamboo is demonstrated to be an environmentally friendly precursor to synthesize the high-performance anode material of KIBs. And it also provides a strategy to stabilize carbon-based anode materials by regulating their structure and composition in the synthetic process.