Pyrolytic gas exfoliation and template mediation inducing defective mesoporous carbon network from industrial lignin for advanced lithium-ion storage

Abstract

Enzymatic hydrolysis lignin (EHL) from the biorefinery industry has been considered an ideal carbon source to prepare high-performance carbonaceous electrodes due to its high aromaticity and abundance. However, the severe agglomeration of the directly carbonized EHL results in insufficient lithium storage sites and inferior transfer kinetics. Herein, a delicate strategy of pyrolytic gas exfoliation and template mediation through ZnCO3 and ZnC2O4 decomposition was developed to engineer the microstructure of EHL-derived carbonaceous material (ECM) at 650 °C for robust lithium storage. The mesoporous ECM with an interconnected grape-like (200 nm) network is prepared by single CO2 exfoliation and ZnO templating. Surface micropores are engineered by temporary ZnO activation at 500–650 °C. The blocky ECM with coexisting micro/mesopores is prepared by dual CO/CO2 exfoliation and ZnO templating. The tempestuous release of CO2 produces deep micropores. The developed mesoporous structure boosts fast Li-ion transportation and accessibility for defects. In addition, the nanostructured grape-like (200 nm) network exposes active surface defects and shortens the charge-diffusion distance. Thus, the mesoporous ECM displays a robust capacity (534.1 mAh·g−1 at 0.2 A·g−1), superior rate capability (323.4 mAh·g−1 at 1 A·g−1) and excellent cycling stability. The blocky ECM with coexisting micro/mesopores shows better lithium storage performance than the microporous blocky ECM prepared by ZnCl2 activation.