Constructing practical micron silicon anodes via a homogeneous and robust network binder induced by a strong-affinity inorganic oligomer

Designing robust binders has been demonstrated to be an effective and facile strategy to stabilize Si anodes. However, the binders that performed well for Si nanoparticles are not applicable for low-cost and accessible Si micron-powders. Hence, a novel binder design strategy is still greatly required for practical micron-Si anodes. Herein, a robust water-based network binder (named as c-PTP-Alg) has been designed via coupling potassium tripolyphosphate (PTP) inorganic oligomer with alginic acid (Alg) organic macromolecule. Owing to the unique structure of PTP, a network with high mechanical resistance can be constructed in c-PTP-Alg binder via strong ion-dipole interactions. Moreover, the highly soluble and dispersed PTP inorganic oligomer in water prevents the organic macromolecule from aggregation. This induces a homogeneous texture in the c-PTP-Alg binder, which enables the polar groups in the composite binder to anchor micron-Si particles efficiently. Therefore, by simply applying the c-PTP-Alg binder, a significantly improved electrochemical performance of micron-Si anode with a high reversible capacity of 1599.9 mAh g-1 after 100 cycles at 3000 mA g-1 has been obtained. More specially, the high-energy-density Si||S-PAN full cells have also been constructed, showing the practical application prospect of the c-PTP-Alg binder.