A highly reversible Zn anode enabled by organic/inorganic Bi-protective layer

Aqueous Zn-ion batteries (AZIBs) are regarded as one of the most promising large-scale energy storage system due to the merits of low cost and safety. However, uncontrolled Zn dendrite caused by uneven Zn2+ deposition on the surface of Zn anode is a serious challenge for the development of Zn anode. In this work, an organic/inorganic bi-protective layer is constructed on Zn electrodes and features an inorganic layer (MXene) at the bottom and a polymer layer sulfonated poly(ether ketone)(SPEEK) on the top. MXene is porous and conductive, which can diminish the local current density and have a shunting impact on Zn2+. SPEEK has good mechanical qualities to reduce the volume effect of Zn during charge/discharge procedure and avoid the direct contact among Zn and electrolyte. Therefore, the bi-protective layer SPEEK/MXene (SKME) can both limit side effects and decrease dendrite development. Therefore, the SKME@Zn electrode has extremely long plating/stripping cycling period of 1300 h at 0.5 mA cm−2. The SKME@Zn//V2O5 full batteries display higher cycle stability than the bare Zn//V2O5 and MXene@Zn//V2O5 systems, indicating that this organic/inorganic bi-protective layer has practical application prospects.