Controllable synthesis of mesoporous carbon microspheres with renewable water glass as a template for lithium-sulfur batteries
By Cai, Wendi; Ruan, Songju; Ma, Cheng; Liu, Xiaojun; Wang, Jitong; Qiao, Wenming; Ling, Licheng
Published in Journal of Colloid and Interface Science
2019
Abstract
Mesoporous carbon microspheres (MCMs) were prepared via a spray drying-assisted template method using resorcinol-formaldehyde as the carbon precursor and water glass as the template. The pore structure could be controlled by adjusting the hydrolysis time, hydrolysis temperature, concentration of the water glass and reactant ratio. Water glass could be recycled after use, making this strategy environmentally friendly and cost-effective. MCMs with three-dimensional interconnected networks, high surface area (852–1549 m2 g−1), large pore volume (1.7–2.1 cm3 g−1) and controllable pore diameter (3.8–15.1 nm) were constructed and have good electrical conductivity and a large volume for sulfur loading. The S/MCM composites with abundant residual nanochannels could not only benefit for the diffusion of electrolyte but also improve the utilization of sulfur and buffer the volume expansion of sulfur. The MCMs with relatively small mesopores manifest a high reversible capacity and rate performance owing to the strong confinement effect of polysulfides. MCM-1 delivered an initial capacity of 888.7 mA h g−1 under 0.5C with a capacity retention of 700.5 mA h g−1 after 100 cycles. The good electrochemical performance confirms that mesoporous carbon microspheres can be an excellent host material for sulfur cathodes.