Aqueous\nSupramolecular Binder for a Lithium–Sulfur\nBattery with Flame-Retardant Property

Abstract

A lithium–sulfur\n(Li–S) battery based on multielectron\nchemical reactions is considered as a next-generation energy-storage\ndevice because of its ultrahigh energy density. However, practical\napplication of a Li–S battery is limited by the large volume\nchanges, insufficient ion conductivity, and undesired shuttle effect\nof its sulfur cathode. To address these issues, an aqueous supramolecular\nbinder with multifunctions is developed by cross-linking sericin protein\n(SP) and phytic acid (PA). The combination of SP and PA allows one\nto control the volume change of the sulfur cathode, benefit soluble\npolysulfides absorbing, and facilitate transportation of Li⁺. Attributed to the above merits, a Li–S battery with the\nSP–PA binder exhibits a remarkable cycle performance improvement\nof 200% and 120% after 100 cycles at 0.2 C compared with Li–S\nbatteries with PVDF and SP binders. In particular, the SP–PA\nbinder in the electrode displays admirable flame-retardant performance\ndue to formation of an isolating layer and the release of radicals.