Ionic-cellulose-adhesive modulated aqueous electrolyte enables water-poor and stable anion-derived electrolyte interphase for durable and dendrite-free zinc metal batteries

The development of aqueous zinc-ion batteries (ZIBs) as attractive candidates is largely limited by the unstable anode/electrolyte interface (AEI), which causes dendrite formation and by-products. Here, an inexpensive ionic cellulose adhesive, carboxymethylcellulose sodium (CMC), is utilized as an interface stabilizer to controllably manipulate the AEI for reversible Zn plating/stripping behaviors. The CMC derived anions have a propensity to initially gather on the Zn surface, forming a unique H2O-poor and CMC--rich electrical double layer (EDL) for relieving the water-induced side reactions and promoting fast Zn2+ transport kinetics. Meanwhile, an adaptive solid electrolyte interphase (SEI) can be triggered during cycling to further tune interfacial Zn2+ deposition behaviors. Such a combination enables exposure of (002) facets with dendrite-free and compact Zn deposition on Zn metal. Accordingly, the Zn//Zn symmetric cells with CMC-based electrolyte achieve outstanding lifespan with a 26-fold enhancement for 3125 h at 1 mA cm−2 and 1 mA h cm−2. Also, the Zn anode is promoted to run over 4000 cycles with high Zn reversibility of 99.7%. When paired with NaV3O8·1.5 H2O (NVO) cathode, the full cell with CMC achieves a prominent stability for 2500 cycles at 3 A g−1, much better than that in pure ZnSO4 electrolyte.