Flexible TiCT/Nanocellulose Hybrid Film as a Stable Zn-free Anode for Aqueous Hybrid Zn-Li Batteries.

Aqueous zinc-based batteries are a very promising technology in the post-lithium era. However, excess zinc metals are often used, which results in not only making a waste but also lowering the actual energy density. Herein, a TiCT/nanocellulose (derived from soybean stalks) hybrid film is prepared by a facile solution casting method and employed as the zinc-free anode for aqueous hybrid Zn-Li batteries. Benefiting from the ultra-low diameter and rich hydroxyl groups of nanocellulose, the hybrid film exhibits better mechanical properties, superior electrolyte wettability, and more importantly, significantly improved zinc plating/stripping reversibility compared to the pure TiCT film. The hybrid film also dramatically overwhelms the stainless steel as the electrode for reversible zinc deposition. Further analysis shows that the hybrid film can lower the zinc deposition overpotential and promote the desolvation process of hydrated Zn ions. In addition, it is found that hexagonal Zn thin flakes are horizontally deposited onto the hybrid film owing to the low lattice mismatch between the TiCT surface and the (002) facet of Zn. Consequently, zinc dendritic growth and accompanied harmful side reactions can be considerably inhibited by the hybrid film, and the assembled Zn-Li hybrid batteries exhibit excellent electrochemical performances. This work might inspire future work on zinc-based batteries.