Rational design of a dual-gradient zincophilic-conductive interphase for dendrite-free zinc batteries

The rampant "top-growth" dendrites on Zn anodes restrict the implementation of up-and-coming aqueous zinc batteries. Here we design a dual-gradient interphase composed of a top carbon-fiber layer and a bottom argentiferous layer (CF/Ag-CF@Zn), which delivers longitudinally strengthened zincophilicity and conductivity for bottom-preferential Zn deposition. Such a bifunctional interphase synergistically establishes internal bottom-up gradient ion/electron fluxes, which guide spatially confined Zn deposition at the interphase bottom, thus substantially avoiding short circuits. Meanwhile, a CF/Ag-CF artificial interphase functions as a protective layer on the surface of the Zn anode in aqueous media to block interfacial side reactions. The favorable interphase electrochemistry endows the Zn anode with high deposition/stripping reversibility and an ultralong cycling lifespan of over 6700 h at 5 mA cm −2 with a brilliant cumulative capacity exceeding 16.75 Ah cm −2 . The CF/Ag-CF@Zn|KV 12 O 30− y · n H 2 O full battery delivers excellent stability over 2400 cycles at 5 A g −1 . This work provides a new paradigm for the rational interfacial design of Zn anodes to create dendrite-free Zn metal batteries. A dual-gradient carbon-fiber/argentiferous interphase with longitudinally strengthened zincophilicity-conductivity is devised on a Zn anode, which guides bottom-preferential homogeneous Zn deposition for mitigating Zn dendrites and side reactions.