Combined sustainable production technology of calcium chloride and lignin-derived porous carbon electrode materials

Sustainable co-production of materials and chemicals is essential to green production and reduction of contaminations. This work presents a sustainable production process for the co-production of porous carbon and calcium chloride using renewable lignin as the carbon precursor. The utilization of CaO as a hard template agent facilitates the creation of porous carbons through the homogeneous mixing of lignin precursors and CaO. Theoretically, it is possible to obtain carbon dioxide with high purity from the subsequent acid etching process. CaCl2 with high purity as a value-added product can be obtained by a straightforward crystallization process with a calcium collection efficiency of >93%. In this work, the formation mechanism of the pore structure evolution of LPC was elucidated by exploring the structural evolution of CaO during the reaction process. The obtained LPC has a hierarchical porous structure and specific surface areas around 700 m2 g−1. The obtained porous carbons showed excellent electrochemical performances as the cathodes of zinc ion hybrid capacitors. This combined sustainable production process could be developed as a practical process for the production of calcium chloride and porous carbons.