In situ construction of dual network binder synergistically enables the stability of SiO anodes

Abstract

Silicon monoxide (SiO) is a promising high-capacity anode material for lithium-ion batteries (LIBs), yet its substantial volume expansion during lithiation/delithiation leads to mechanical stress, structural degradation, and rapid capacity fading, thereby limiting practical application. To overcome these challenges, we propose an in situ cross-linking strategy to construct a dual network binder that firmly anchors onto SiO particles through an ester-based covalent framework and dynamic hydrogen bonding, achieved by a one-step thermal reaction of tapioca starch (TA), fumaric acid (FA), and SiO. Multi-scale testing reveals that the branched TA structure provides abundant hydroxyl groups for strong covalent cross-linking, while the hydrogen bond network imparts self-healing capability and volume-change adaptability. Simultaneously, anchoring polar groups to the SiO surface enhances interfacial adhesion. This synergistic dual network architecture binder effectively dissipates stress and preserves electrode integrity, ensuring continuous Li⁺ transport. As a result, the TA–FA modified SiO anode delivers exceptional cycling stability, maintaining a high reversible capacity of 921.7 mAh g⁻¹ after 300 cycles at 1 A g⁻¹, far surpassing the sodium alginate (SA)/SiO (443.1 mAh g⁻¹). This study utilizes natural polymer architectures to create a covalent-hydrogen bond dual network binder via an in situ route, offering a novel strategy for developing high-performance SiO anodes in practical LIBs.