SPAN secondary particles enabled high energy density Lithium-Sulfur battery

Micro-sized SPAN secondary particles were prepared by a scalable spray drying (SD) technique, during which an ion conductive composite polymer composed of physiochemically crosslinked polydopamine (PDA), polyacrylic acid (PAA) and polyvinyl alcohol (PVA) was coated onto the primary particles. The secondary particles enable the Li-SPAN (1.0–3.0 V) prototype cells with enhanced energy density of 530.2 Wh/kg. [Display omitted] •SPAN secondary particles were prepared by spray drying.•The crosslinked polymer network promoted ion transport within the secondary particles.•The composite coating also enhanced the electrode stability.•Prototype LSB with energy density up to 530.2 Wh kg−1 was obtained. High-areal-capacity electrodes and lean electrolyte are practical approaches for batteries to enhance their energy density, while it’s challenge for the lithium-sulfur batteries using nano-sized sulfurized polyacrylonitrile (SPAN) cathodes due to the sluggish charge transportation. Here, a spray-drying (SD) technique for mass production of micron-sized SPAN secondary particles (PC-SPAN) with composite coating is proposed. The composite involves polydopamine (PDA), polyacrylic acid (PAA) and polyvinyl alcohol (PVA) that physiochemically crosslinking. The rich catecholamine, hydroxyl and carboxyl groups not only construct strong and flexible adhesion among the SPAN primary particles to keep the electrode integrity, but also render built-in ion passage within the secondary particles to allow the electrode working under lean electrolyte condition. Consequently, PC-SPAN electrode with a high areal loading of 8.4 mg cm−2 delivers a higher specific capacity of 547.4 mAh g−1 at 0.3C when that of SPAN is less than 400.0 mAh g−1. In the meantime, prototype Li-SPAN battery with high energy density of 530.2 Wh kg−1 is achieved using PC-SPAN electrode with an areal capacity of 19.1 mAh cm−2 and low electrolyte/SPAN ratio of 0.93 μL mg−1, which demonstrates the feasibility of this strategy toward applicable high energy LSBs.