Porous Carbon Anodes for a High Capacity Lithium-Ion Battery Obtained by Incorporating Silica into Benzoxazine During Polymerization

Porous carbon anodes with a controllable V-mes/V-mic ratio were synthesized through the self-assembly of poly(benzoxazine-co-resol) and the simultaneous hydrolysis of tetraethyl orthosilicate (TEOS) followed by carbonization and removal of silica. The V-mes/V-mic ratio of the carbon can be controlled in the range of approximately 1.3-32.6 through tuning the amount of TEOS. For lithium-ion battery anodes, a correlation between the electrochemical performance and V-mes/V-mic ratio has been established. A high V-mes/V-mic ratio in porous carbons is favorable for enhancing the accessibility of Li ions to active sites provided by the micropores and for achieving good lithium storage performance. The obtained porous carbon exhibits a high reversible capacity of 660 mAh g(-1) after 70 cycles at a current density of 100 mA g(-1). Moreover, at a high current density of 3000 mA g(-1), the capacity still remains at 215 mAh g(-1), showing a fast charge-discharge potential. This synthesis method relying on modified benzoxazine chemistry with the hydrolysis of TEOS may provide a new route for the development of mesoporous carbon-based electrode materials.