A biomass-rich, self-healable, and high-adhesive polymer binder for advanced lithium-sulfur batteries.

Although lithium-sulfur (Li-S) batteries have attracted a great deal of attention due to their ultrahigh energy density, the significant dissolution and shuttle of polysulfides, coupled with the unstable electrode structure, result in a substantial decline in capacity, thereby hindering their practical application in rapidly advancing energy storage systems. In this work, we prepare an environmentally friendly binder (LA-GA) that possesses self-healing abilities and high adhesion by combining dynamic disulfide (SS) bonds with abundant polar functional groups. Significantly, the self-healing capability provided by SS bonds facilitates the repair of cracks resulting from cathode volume expansion. Simultaneously, the polar functional groups (carboxyl and pyrogallol) not only enhance adhesion, preserving cathode integrity, but also effectively participate in lithium polysulfide adsorption, thereby inhibiting the shuttle effect. As a result, sulfur cathodes incorporating the LA-GA binder demonstrate favorable cycling stability, with a high capacity retention of 81.9 % when tested at 0.2C for 100 cycles. Additionally, the long-term cycling performance is satisfactory, showing a small capacity decline rate of 0.0469 % per cycle over 700 cycles at 1.0C.