3D Interconnected Porous Carbon Aerogels as Sulfur Immobilizers for Sulfur Impregnation for Lithium-Sulfur Batteries with High Rate Capability and Cycling Stability

摘要

To eliminate capacity-fading effects due to the loss of sulfur cathode materials as a result of polysulfide dissolution in lithium-sulfur (Li-S) cells, 3D carbon aerogel (CA) materials with abundant narrow micropores can be utilized as an immobilizer host for sulfur impregnation. The effects of S incorporation on microstructure, surface area, pore size distribution, and pore volume of the S/ CA hybrids are studied. The electrochemical performance of the S/CA hybrids is investigated using electrochemical impedance spectroscopy, galvanostati-cal charge-discharge, and cyclic voltammetry techniques. The 3D porous S/CA hybrids exhibit significantly improved reversible capacity, high-rate capability, and excellent cycling performance as a cathode electrode for Li-S batteries. The S/CA hybrid with an optimal incorporating content of 27％ S shows an excellent reversible capacity of 820 mAhg~(-1) after 50 cycles at a current density of 100 mAg~(-1). Even at a current density of 3.2C (5280 mAg~(-1)), the reversible capacity of 27％S/CA hybrid can still maintain at 521 mAhg~(-1) after 50 cycles. This strategy for the S/CA hybrids as cathode materials to utilize the abundant micropores for sulfur immobilizers for sulfur impregnation for Li-S battery offers a new way to solve the long-term reversibility obstacle and provides guidelines for designing cathode electrode architectures.