Polysaccharide from Loquat Leaves to Prepare Hierarchical Porous Carbon as a Matrix for Active Sulfur

Abstract

Fossil fuel exhaustion and overdevelopment usually lead to a recession, which is worsened by the environmental pollution. So it is of high priority to develop high-efficiency energy storage device. Here, a green and environment-friendly strategy is devised to fabricate carbon materials from biomass. By water extraction and alcohol precipitation, polysaccharide is extracted from loquat leaves. After calcining under high temperature, hierarchical porous carbon materials (HPCM) are obtained, possessing a variety of macropores, mesopores and micropores. Such ample and hierarchical pores enable the electrolyte infiltration and the buffering of the volume expansion of sulfur in repeated electrochemical reactions. The structure stability of the entire electrode can thus be well maintained. When evaluated as the scaffold for sulfur, the electrochemical performance of carbon/sulfur composite was tested. Even after 500 cycles, the reversible capacity is retained as high as 485.4 mA·h/g at the current density of 1.6 A/g. It also offers a notable rate capability, attaining the discharge capacity of 700.7 mA·h/g at 2 C. All the electrochemical performance results prove the feasibility of the proposed strategy.