High-energy and dendrite-free solid-state zinc metal battery enabled by a dual-network and water-confinement hydrogel electrolyte

Undesirable side reactions and uncontrollable dendrite growth on zinc anode surface severely restrict the practical applications of the rechargeable zinc-ion batteries (RZIBs). In this work, a lignin-containing cellulose nanofibers (LCNF)-polyacrylamide hydrogel (LPH) electrolyte with a unique dual-network structure and excellent water-retaining property is developed for high-energy and dendrite-free solid-state zinc-ion batteries. Benefiting from these advantages, the activity of water molecule in LPH is limited and the water-induced side reactions are restricted, leading to a significantly widen voltage window. Assembled with LPH electrolyte, the Zn/Zn symmetric cells can maintain a long cycling lifespan of 4000 h at the current density of 0.5 mA cm−2 under 1 mAh cm−2. With LPH electrolyte, Zn/MgVO full batteries delivered a high capacity of 149.2 mAh/g with the capacity retention of 91.9 % after 4000 cycles at 5 A/g. Moreover, with a widened voltage window of 0.2 V to 1.9 V, the full batteries with LPH can deliver a high energy density of 255.4 Wh kg−1 at the power density of 341.7 W kg−1 for over 5000 cycles. This design of LPH electrolyte provides a new insight to stabilize the zinc anode and achieve high energy density for the further development of RZIBs.