【摘要】 单质硫及其放电最终产物Li₂S的绝缘性以及两者密度差异引起的结构坍塌等问题严重阻碍了锂硫电池的进一步发展，找寻合适的基体材料是解决上述问题的有效策略。本工作选用一种蜂窝状多孔碳作为硫正极的基体材料，通过常规的熔融扩散法将硫单质固定在碳孔隙中，并利用SEM、XRD、XPS和BET等方法对多孔碳@单质硫复合材料进行了表征。结果表明，硫单质均匀地负载在碳骨架中。同时，蜂窝状结构碳不仅为硫单质提供了电子导电网络，也保证了正极的稳定性。更重要的是，蜂窝状的结构为循环过程中硫正极的体积膨胀提供了一定的缓冲空间，缓解了结构坍塌这一问题。此外，碳基体丰富的孔隙度在一定程度上减少了多硫化物的穿梭。因此，在0.1C的倍率下，多孔碳@单质硫复合材料首次放电比容量高达1 125.9 mAh/g, 300次循环后比容量可保持305.1 mAh/g。更多还原

【Abstract】 The further development of lithium sulfur battery is severely hindered by the insulation of elemental sulfur and its final product Li₂S as well as the structural collapse caused by their density difference, so finding a suitable carrier material is an efficient strategy to address the above-mentioned problems. In this work, a honeycomb-like porous carbon is selected as the host material for the sulfur cathode, the sulfur is immobilized in the pores of porous carbon by conventional melt diffusion method, and porous carbon@sulfur composite is characterized by SEM, XRD, XPS and BET techniques. The results show that the sulfur was uniformly loaded in the carbon skeleton. Meanwhile, the high electrical conductivity and honeycomb-like structure of porous carbon not only provide an electronic conductive network for the sulfur, but also ensures the stability of the cathode. More importantly, the honeycomb structure gives some buffer space for the volume expansion of the sulfur cathode during the cycling process, which lessens the trouble of structural collapse. In addition, the abundant pores in the host material decrease the shuttling of polysulfides to some extent. Therefore, the specific capacity of porous carbon@sulfur composite can deliver 1 125.9 mAh/g at 0.1C during the first discharging and maintain 305.1 mAh/g after 300 cycles.更多还原