Three-Dimensional Crosslinked PAA-TA Hybrid Binders for Long-Cycle-Life SiO_x Anodes in Lithium-Ion Batteries

The large volume expansion hinders the commercial application of silicon oxide (SiOx) anodes in lithium-ion batteries. Recent studies show that binders play a vital role in mitigating the volume change of SiOx electrodes. Herein, we introduce the small molecule tannic acid (TA) with high branching into the linear poly(acrylic acid) (PAA) binder for SiOx anodes. The three-dimensional (3D) crosslinked network with multiple hydrogen bonds is formed by the incorporation of abundant hydroxyl groups with unique carboxyl groups, which increases the interfacial adhesive strength with SiOx particles. As a consequence, SiOx electrodes based on the PAA-TA binder show an excellent cycling performance with a high specific capacity of 1025 mA h g–1 at 500 mA g–1 after 250 cycles. Moreover, the SiOx||NCM811 full cell exhibits a reversible capacity of 143 mA h g–1 corresponding to 87.4% capacity retention after 100 cycles.