Nickel ion-anchored helical braided binder network with soft-rigid synergy and self-recovery ability for high-performance silicon anode

Abstract

Silicon (Si) is one of the most promising anode materials for high-capacity lithium-ion batteries. However, its drastic volume changes during cycling lead to fast capacity decay. Binders play an important role in maintaining the structural integrity of electrodes. This paper proposes a three-dimensional binder network, which synthesized by weaving Ni2+ anchored soft gellan gum chains with linear rigid polyvinyl alcohol chains. Benefiting from the soft-rigid synergy and self-recovery ability of the obtained binder, the Si anode delivers over 1500 mAh g−1 after 500 cycles at 2.1 A g−1, and post-analysis proofs that this binder can buffer the volume changes of Si particles and retain the overall stability of the electrode. In addition, the optimized Si anode still have a high capacity retention of ca. 50% even at 84 A g−1, because the binder network can provide uniform Li+ flux and more Li+ transport channels for the electrode.