Coconut-Solid-Waste-Derived Hard-Carbon Anode Materials for Fast Potassium Ion Storage

Hard carbon, which features recyclability, low costs, and environmental friendliness, is an attractive anode material for K+ storage. Nevertheless, the state-of-the-art hard carbon is still unsatisfactory due to its poor multiplication performance and unclear energy storage mechanism. In this study, a one-pot carbonisation method using coconut solid waste biomass is applied to obtain high-performance hard-carbon (CHC) anode materials. The microstructure and electrochemical properties of the CHC are investigated at different carbonisation temperatures (1100–1500 °C). The CHC materials prepared at 1300 °C (CHC1300) have a high capacity of 265.8 mAh g−1 at a current density of 25 mA g−1 and a superior cyclability of 1000 cycles at 1.0 A g−1 with a capacity retention of 96.6%. This approach, referred to as the “biomass-to-application” strategy, holds promise for advancing the development of cost-effective and sustainable KIBs.