Interface engineering of electron-ion dual transmission channels for ultra-long lifespan quasi-solid zinc-ion batteries

• Electron-ion dual transmission channels were established via PEDOT:PSS. • PEDOT chains offer electron transfer channels to promote fast charge exchange. • PSS chains provide ion transmission channels to accelerate the migration of Zn 2+ ions. • Ultra-long lifespan of 6750 h and 520 h with a DOD of 60 % are realized in this design. Hydrogel electrolytes have emerged as effective strategies to prolong the lifespan of aqueous zinc ion batteries (AZIBs). However, dendrites and side reactions are still inescapable due to the residual active water and chaotic migration of Zn 2+ . Herein, a super stable Zn anode is realized through the synergistic effect of interfacial electron-ion dual transmission channels (EIDC) and an intermediate sodium alginate (SA) gel. Specifically, the SA gel can adjust the solvation structure of Zn 2+ and weaken the strong bonding of Zn 2+ and H 2 O molecules. The EIDC polymer layer (PEDOT:PSS) is engineered on the SA hydrogel surfaces, in which PSS chains can offer uniform ion transmission channels via the electrostatic interaction between SO 3 – groups and Zn 2+ . While another PEDOT chains can provide electron conducting channels through the conjugated π- π bonds to accelerate charge exchange. Benefiting from the synergistic effect of EIDC polymer layer and SA gel, the as-prepared SA/EIDC gel electrolyte achieves a high ionic conductivity of 41 mS cm –1 . The Zn//Zn symmetric batteries exhibit a super-long lifespan of 6750 h at 1 mA cm –2 and 1 mAh cm –2 (>9 months), and cycling life of MnO 2 -Zn full battery surpasses 4000 cycles. This work presents a new perspective on designing hydrogel electrolytes towards ultra-long lifespan ZIBs. The EIDC polymer layers (PEDOT:PSS) is engineered on the SA hydrogel surfaces, in which PSS chains can offer uniform ion transmission channels via the electrostatic interaction between SO 3 – groups and Zn 2+ . While another PEDOT chains can provide electron conducting channels through the conjugated π π bonds to accelerate charge exchange.