Sulfurized Polyacrylonitrile Impregnated Delignified Wood-Based 3D Carbon Framework for High-Performance Lithium–Sulfur Batteries

Abstract

Sulfurized polyacrylonitrile (SPAN) is a promising cathode active material capable of suppressing lithium polysulfide dissolution in lithium–sulfur (Li–S) batteries. However, due to the low S content in SPAN, achieving a high SPAN areal loading without compromising specific capacity and cycling stability would be required. To address this challenge, we took advantage of the inherent porous structure of natural wood and engineered carbonized delignified wood (CDW) frameworks using a delignification/low-temperature pyrolysis approach. The unique design of the SPAN-impregnated CDW (SPAN@CDW) electrode, wherein the interconnected pathways run in three dimensions, ensures effective electron and ion transport within the electrode. Biomass-derived SPAN@CDW cathodes exhibited an excellent rate capability compared to the popular synthetic 3D scaffolds, such as graphene foam cathodes, with discharge capacities >1000 mA h gs–1 at 1 C (1672 mA g–1). Electrodes with CDW pyrolyzed at 600 °C, and a S areal loading of ∼2 mg cm–2 exhibited a high specific capacity of ∼1350 mA h gs–1 after 500 cycles at 0.1 C, indicating good cycling stability. We also demonstrated the sustainable fabrication of SPAN@CDW electrodes with high SPAN loadings up to ∼35 mg cm–2, which could deliver a high areal capacity of ∼15.1 mA h cm–2 at 0.1 C.