Preparation of macadamia nut shell porous carbon and its electrochemical performance as cathode material for lithium–sulfur batteries

Abstract

Biomass carbon material as the sulfur storage matrix of lithium–sulfur batteries is one of the research hotspots. In this paper, the macadamia nut shells are used as the precursor to prepare porous carbon material. By exploring the effect of temperature on the microstructure and electrochemical performance of porous carbon materials during activation, it is found that the porous carbon material prepared under the activation condition of 900 °C has a developed pore structure, super high specific surface area (3552.7 m2•g−1), larger pore volume (2.2 cm3•g−1) and higher mesoporous content (23.85%). And the composite cathode material with the sulfur content of 70.1% has the highest specific capacity, and the initial discharge specific capacity for 0.2 C can reach 942.4 mAh•g−1. The composite material S/OCNT@OPC-1:1 obtained by compounding it with carbon nanotubes at a mass ratio of 1:1 has higher specific capacity, better rate performance and cycle performance. At 0.2 C, the initial discharge specific capacity is as high as 1252.6 mAh•g−1, and it remains at the level of 717.3 mAh•g−1 after 200 cycles. Even at 1 C, the specific capacity is still 984.3 mAh•g−1, and it remains at 690.9 mAh•g−1 after 200 cycles, and the capacity retention rate is 70.2%. Our work shows that the composite material obtained by combining low-cost biomass carbon materials and carbon nanotubes as the cathode material for lithium-sulfur batteries has obvious advantages.