Balsa wood derived three-dimensional hierarchical porous carbon materials as an anode material for K-ion batteries

Bio-based hard-carbon materials were attracted wide-ranging attention in environmental protection and energy conversion with the advantages of low cost as well as recyclability. In this work, three-dimensional hierarchical porous hard carbon materials were synthesized by using the world's lightest commercial balsa wood as the carbon source and further activated with strong alkali and calcium chloride. The as-modified carbon material exhibited a larger specific surface area of 499.4 m(2)g(-1) (compared to 283.2 m(2)g(-1) before modification) with a wide range of macropores, mesopores, and micropores, which can shorten the distance of diffusion to the inner surface and provide fast transmission channels for K-ions, resulting in an obvious enhanced reversible specific capacity and rate performance compared to untreated one. This work provides a reference for the utilization of industrial waste balsa wood residues in large-scale energy system.