Triethanolamine-modified binder with synergistic effects on Zn anode in improving the cycling stability of aqueous rechargeable Zn[sbnd]Ni batteries

Abstract

Aqueous rechargeable ZnNi batteries (ARZNBs) have been broadly considered as beyond-lithium energy-storage devices owing to their safety and potentially high energy density. However, the current practical ARZNBs suffer from short-circuit attack led by inherent problem of zinc anodes. Among the optimization methods of Zn anodes, proper binder engineering of anode is a facile and competitive solution, which is potentially needed to confront the problem of Zn dendrite, poor zinc reversibility, and the difficulties in enlargement for practical production. Herein, Zn anode is fabricated by simply mixing the triethanolamine (TEA) with traditional binder glue via aqueous processing. Specifically, it is composed of the commercial available chemical additive, triethanolamine (TEA), exploiting polyvinyl alcohol (PVA) substrate and potassium polyacrylate (PAAK) additive to retain water and help dissolve PVA. While the TEA helps to achieve the better dispersing and wetting properties of slurry, together with the stable interface structure and better electrolyte tolerance of anode. Notably, the leveling effect of TEA on anode is proved in this strategy, which is beyond the traditional approaches of adding additives to electrolyte. As a result, the scale-up large-area ZnNi pouch battery (∼3 Ah) prepared using this composite binder delivers ultra-long and stable galvanostatic cycling performance (∼1.3 V, >450 cycles and 1200 h) and superior energy efficiency compared to the benchmark of traditional anode, with considerable cyclic discharge loading (∼753 mA g−1Zn and ∼75 mA cm−2). The TEA-modified binder with synergistic effects on Zn anode offers a promising avenue to build low-cost and high-performance ARZNBs.