Chang Li

Aqueous Zn ²⁺ /Zn||MnO ₂ /Mn ²⁺ batteries - operating on electrodeposition/dissolution - offer promising high-voltage, high-capacity grid storage capabilities but require acidic conditions for MnO ₂ /Mn ²⁺ conversion that induces problematic zinc corrosion. Here we present a global approach that identifies deep eutectic aqueous-organic electrolytes that strategically disrupt water's hydrogen bonding network, simultaneously enhancing MnO ₂ reversibility at the cathode without OER while enabling stable zinc cycling at the anode without HER. Such non-flammable electrolytes regulate the cation solvation structure and phase of the deposited MnO ₂ and its morphology, promoting layered structures with enhanced ion transport pathways that significantly improve stripping efficiency. These deep eutectics increase the oxygen evolution overpotential by 0.6 V, well above the MnO ₂ deposition potential, which completely suppresses unwanted O ₂ evolution. Moreover, they alter the local environment at the cathode interface to create localized interfacial pH gradients that influence critical processes, including optimizing proton transport and MnO ₂ stripping. Our Zn ²⁺ /Zn||MnO ₂ /Mn ²⁺ dual-electrode-free battery achieves high Coulombic efficiency for extended cycling (>5000 cycles) without external acid addition, advancing high-energy-density zinc-manganese battery development through rational electrolyte design.

We report a solvent-designed Mg(TFSI)₂ electrolyte, which facilitates ion pair dissociation, nanoscale Mg nucleation/growth, and dendrite-free Mg plating/stripping at 2 mA h cm⁻², enabling full cell operation up to 3.5 V at a 2C rate for 400 cycles.

Two major challenges hinder the advance of aqueous zinc metal batteries for sustainable stationary storage: (1) achieving predominant Zn-ion (de)intercalation at the oxide cathode by suppressing adventitious proton co-intercalation and dissolution, and (2) simultaneously overcoming Zn dendrite growth at the anode that triggers parasitic electrolyte reactions. Here, we reveal the competition between Zn²⁺vsproton intercalation chemistry of a typical oxide cathode using ex-situ/operandotechniques, and alleviate side reactions by developing a cost-effective and non-flammable hybrid eutectic electrolyte. A fully hydrated Zn²⁺solvation structure facilitates fast charge transfer at the solid/electrolyte interface, enabling dendrite-free Zn plating/stripping with a remarkably high average coulombic efficiency of 99.8% at commercially relevant areal capacities of 4 mAh cm⁻²and function up to 1600 h at 8 mAh cm⁻². By concurrently stabilizing Zn redox at both electrodes, we achieve a new benchmark in Zn-ion battery performance of 4 mAh cm⁻²anode-free cells that retain 85% capacity over 100 cycles at 25 °C. Using this eutectic-design electrolyte, Zn | |Iodine full cells are further realized with 86% capacity retention over 2500 cycles. The approach represents a new avenue for long-duration energy storage.

Metal–organic frameworks (MOFs), such as Prussian blue and its analogues (PB and PBAs) with open frameworks have attracted tremendous attentions as cathode materials for sodium‐ion batteries, owing to their simple method of synthesis and high theoretical specific capacity. In this study, core–shell‐structured PBAs are prepared by an in situ self‐assembly method. Owing to the advantages of both constituents, the as‐prepared core–shell PBAs show excellent rate and cycling electrochemical properties through a dual‐level‐controlled charge–discharge depth mechanism. It delivers a specific capacity of 104.3 mAh g⁻¹ at 0.1 C, as well as a remarkably enhanced cycle performance, giving 88.3 % of its initial capacity over 1000 cycles at 300 mA g⁻¹. In particular, the coating strategy described herein could be extended to other MOF materials, leading to wider application in energy storage.