Water-Based Dual-Cross-Linked Polymer Binders for High-Energy-Density Lithium-Sulfur Batteries

作者：Yi, Huan; Yang, Yu; Lan, Tu; Zhang, Tian; Xiang, Shuhuai; Tang, Tian; Zeng, Hongbo; Wang, Chaoyang; Cao, Yuliang; Deng, Yonghong^*

来源：ACS applied materials & interfaces, 2020, 12(26): 29316-29323.

DOI：10.1021/acsami.0c05910

• polymer binder
• lithium-sulfur battery
• dual-cross-linking
• high mass loading
• cycle stability

High-mass-loading electrodes with long-term stability have long been a great challenge for lithium-sulfur batteries (LSBs), since the conventional binders are unable to cope with the shuttling of lithium polysulfides and the structural damage in an electrode. Here, a novel water-based polymer, polyphosphate acid cross-linked chitosan ethylamide carbamide (PACEC), is developed as a binder to construct high-energy-density sulfur cathode and flexible LSBs. With a dual-cross-linked network, the PACEC shows excellent affinity with lithium polysulfides to relieve the shuttle effect and robust mechanical properties to stabilize the electrode. The sulfur cathode based on PACEC demonstrates a high sulfur loading of 14.8 mg cm(-2), the areal initial capacity of 17.5 mAh cm(-2), and Coulombic efficiency of 99.3%, while the amount of electrolyte is strictly limited to 6 mu L mg(-1). More importantly, a robust pouch cell with an area of 6 cm(2) and only 177% oversized lithium can successfully integrate the energy density of 6.5 mAh cm(-2) with the cycling retention per cycle of 99.74% during 270 cycles and flexibility at a curvature of 3 mm. This study provides inspirations for the design of eco-friendly polymer binders and paving new ways for the development of LSBs.

• 单位
  1; 华南农业大学; 6; 武汉大学