Remarkable Effect of Sodium Alginate Aqueous Binder on Anatase TiO2 as High-Performance Anode in Sodium Ion Batteries

Sodium alginate (SA) is investigated as the aqueous binder to fabricate high-performance, low-cost, environmentally friendly, and durable TiO2 anodes in sodium-ion batteries (SIBs) for the first time. Compared to the conventional polyvinylidene difluoride (PVDF) binder, electrodes using SA as the binder exhibit significant promotion of electrochemical performances. The initial Coulombic efficiency is as high as 62% at 0.1 C. A remarkable capacity of 180 mAh g-1 is achieved with no decay after 500 cycles at 1 C. Even at 10 C (3.4 A g-1), it remains 82 mAh g-1 after 3600 cycles with approximate 100% Coulombic efficiency. TiO2 electrodes with SA binder display less electrolyte decomposition, fewer side reactions, high electrochemistry reaction activity, effective suppression of polarization, and good electrode morphology, which is ascribed to the rich carboxylic groups, high Young's modulus, and good electrochemical stability of SA binder.