MOF-based ionic sieve interphase for regulated Zn²⁺flux toward dendrite-free aqueous zinc-ion batteries

Targeted at mitigating the inevitable dendrite growth and side reactions in zinc-ion batteries (ZIB), herein, a multifunctional protective strategy of Zn anode coating using zinc benzene tricarboxylate (Zn-BTC) is proposed in the Zn symmetric cell and MnO2//Zn full cell. The rationally selected pores of Zn-BTC served as ionic sieves, accelerating the transport of Zn2+ while blocking the entrance of the electrolyte anions. The structural grids of Zn-BTC hindered the two-dimensional diffusion of Zn2+ and regulated the electric field at the anode, resulting in a uniform flux of Zn2+ and subsequently stable stripping/plating. The Zn-BTC layer also worked as an artificial solid/electrolyte interphase film, expelled the solvated water molecules and restricted the side reactions. As a result, ultra-long cycling stability was achieved, with a superior lifespan of 800 h in the Zn symmetric cell and outstanding capacity retention of 81.1% after 1000 cycles in the MnO2//Zn battery at a high current density of 2 A g-1.