Stabilizing ZnSiO Anode by a Lithium Polyacrylate Binder for Highly Reversible Lithium-Ion Storage.

Binders are crucial for maintaining the mechanical stability of the electrodes. However, traditional binders fail to adequately buffer the volume expansion of ZnSiO anode, causing electrode contact failure and considerable capacity loss during cycling. In this study, we propose a simple and effective solution to address these challenges through a combined strategy of hollow structure design and the introduction of an aqueous lithium poly(acrylic acid) (LiPAA) binder. Hollow structures can shorten ion-transfer distance and accommodate volume change outside. The excellent adhesion of the LiPAA binder created a secure connection between the active ZnSiO particles, conductive additives, and the current collector, which enhanced the mechanical stability and integrity of the electrode. As a result of these positive factors, a ZnSiO electrode using LiPAA as a binder can deliver an excellent capacity of 499 mAh g at a high current density of 5 A g and a long life span of 1000 cycles at 1 A g with a capacity retention of 98%, which significantly outperforms other binders. As demonstrated by X-ray diffraction and X-ray absorption spectroscopy, the storage of lithium ions in ZnSiO follows a dual conversion-alloying mechanism, using Zn as the redox center. In this process, Zn is first reduced to metallic Zn and then forms a LiZn alloy upon lithium-ion insertion. This work shows that LiPAA offers a promising approach to improve the cycling longevity of conversion and alloying anodes in Li-ion batteries.