Ultra-long cycle life flexible quasi-solid-state alkaline zinc batteries enabled by PEDOT:PSS encapsulated Ni3S2 nanorods

Alkaline nickel-zinc (Ni-Zn) batteries are considered as one of the most promising rechargeable battery systems. However, the poor cycling stability of the Ni cathode limit their service life. Herein, a conductive polymer (PEDOT:PSS) encapsulated Ni 3 S 2 hollow nanorod structure via facile immersion is proposed. PEDOT:PSS coating layer can not only provide adhesion for Ni 3 S 2 nanorods to prevent Ni 3 S 2 from falling off the substrate during cycling, but also facilitate electron transfer via the complete conductive pathway. The hollow nanorods structure of Ni 3 S 2 is beneficial to mitigate the volume change and accelerate the rapid transport of ions. Besides, a gel electrolyte with double network porous structure in our battery system is well designed. The ionic association of sodium alginate on Zn 2+ can effectively reduce the activity of bound water molecules in the solvation sheath of Zn 2+ , inhibit the side reaction and dendrite generation through the ion-confinement effect, to achieve uniform deposition of zinc ions . As a consequence, the as-designed quasi-solid-state flexible Ni-Zn battery demonstrates a high specific capacity of 1.06 mAh cm −2 (276.04 mAh g −1 ) at 8 mA cm −2 and an ultra-long cycle stability over 10,000 cycles with a capacity retention of 88.96% at 30 mA cm −2 .