Hierarchical porous carbon derived from the gas-exfoliation activation of lignin for high-energy lithium-ion batteries†
A large scale hierarchical porous carbon material was developed via a cheap and environmentally friendly activation approach using the most abundant aromatic polymer in plants, lignin, and ZnCO3 as a non-corrosive and recyclable activator. The three-dimensional (3D) novel hierarchical lignin-derived porous carbon (HLPC) possesses a desirable microstructure and a large number of mesopores. This structure is achieved by activation from the gas released by ZnCO3, i.e., the gas-exfoliation of lignin and nano-sized ZnO particles (10–20 nm) in situ generated from ZnCO3 have an in situ templating effect. As a result, the resulting HLPC simultaneously achieved excellent volume/mass energy density (730 mA h·cm−3/550 mA h·g−1 after 200 cycles at 0.2 A·g−1) with excellent cycling performance (∼99% retention after 10 000 cycles). In particular, the volume capacitances obtained in our work are the highest among the reported lignin-based carbon materials. Compared to conventional activators, ZnCO3 as a green, non-corrosive, low-cost and recyclable activator has broad prospects in the preparation of biomass-based carbon materials. Our work demonstrates the successful and large-scale conversion of industrial lignin into a high-performance carbon-based material, and the promising mass/volumetric performance further suggests that the method developed may provide an accessible pathway for improving the energy density of energy storage materials.