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

The large volume expansion hinders the commercial application of silicon oxide (SiO_x) anodes in lithium-ion batteries. Recent studies show that binders play a vital role in mitigating the volume change of SiO_x electrodes. Herein, we introduce the small molecule tannic acid (TA) with high branching into the linear poly(acrylic acid) (PAA) binder for SiO_x 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 SiO_x particles. As a consequence, SiO_x 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 SiO_x||NCM811 full cell exhibits a reversible capacity of 143 mA h g^-1 corresponding to 87.4% capacity retention after 100 cycles.