Aqueous Zn‐ion batteries have been considered as promising alternatives to Li‐ion batteries due to their abundant reserves, low price, and high safety. However, Zn anode shows poor reversibility and cycling stability in most conventional aqueous electrolytes. Here, a new type of aqueous Zn‐ion electrolyte based on ZnCl2–acetamide deep eutectic solvent with both environmental and economic friendliness has been prepared. The water molecule introduced in the “water‐in‐deep eutectic solvent” electrolyte could reduce the Zn2+ desolvation energy barrier by regulating Zn2+ solvation structure to promote uniform Zn nucleation. Zn anode shows improved electrochemical performance (≈98% Coulombic efficiency over 1000 cycles) in the electrolyte whose molar ratio of ZnCl2:acetamide:H2O is 1:3:1. The assembled full battery composed of phenazine cathode and Zn anode could stably cycle over 10 000 cycles with a high capacity retention of 85.7%. Overall, this work offers new insights into exploring new green electrolyte systems for Zn‐ion batteries.

A novel polymer with an extended π-conjugated structure (PPh-PTO) can show a delocalized electronic distribution and achieve a higher voltage, excellent cycle life, and good rate capabilities.

Aqueous zinc-ion batteries (AZIBs) have gained extensive attention own to low cost and high safety but are bottlenecked by limited cathode materials. Here, we report an inverse-spinel structured Mg2MnO4 nanosheets...

Uneven deposition and dendrite growth, which lead to capacity fading and short cycling life, are main obstacles that limit the application of Li metal anodes in Li metal batteries. Here, a composite protective layer composed of polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA), SiO 2 nanoparticles, and plasticizer is reported to promote a stable and dendrite-free Li metal anode. The robust layer (≈10 μm) coated on Cu or Li with high ionic conductivity and mechanical strength enables the uniform Li deposition due to the homogeneous Li ion distribution. As a result, the protected Li metal anode shows improved Coulombic efficiencies and cycling stability at various current densities. Full cells containing a LiFePO 4 cathode and a protected Li anode show satisfying capacity retention (96.7% after 250 cycles) and rate capability, even with a limited amount of Li metal in the anode.