Electrocatalytic CO2 reduction reaction (CO2RR) is one of the most promising routes to facilitate carbon neutrality. An alkaline electrolyte is typically needed to promote the production of valuable multi-carbon molecules (such as ethylene). However, the reaction between CO2 and OH– consumes a significant quantity of CO2/alkali and causes the rapid decay of CO2RR selectivity and stability. Here, we design a catalyst–electrolyte interface with an effective electrostatic confinement of in situ generated OH– to improve ethylene electrosynthesis from CO2 in neutral medium. In situ Raman measurements indicate the direct correlation between ethylene selectivity and the intensities of surface Cu–CO and Cu–OH species, suggesting the promoted C–C coupling with the surface enrichment of OH–. Thus, we report a CO2-to-ethylene Faradaic efficiency (FE) of 70% and a partial current density of 350 mA cm–2 at −0.89 V vs the reversible hydrogen electrode. Furthermore, the system demonstrated a 50 h stable operation at 300 mA cm–2 with an average ethylene FE of ∼68%. This study offers a universal strategy to tune the reaction micro-environment, and a significantly improved ethylene FE of 64.5% was obtained even in acidic electrolytes (pH = 2).

High concentration electrolyte (HCE) provides a great opportunity for the development of long-life aqueous zinc (Zn) metal batteries because it can eliminate Zn dendrites and promotes higher Zn Coulombic efficiencies...

The water-in-salt electrolyte (WISE) features intimate interactions between a cation and anion, which induces the formation of an anion-derived solid electrolyte interphase (SEI) and expands the aqueous electrolyte voltage window to >3.0 V. Although further increasing the salt concentration (even to >60 molality (m)) can gradually improve water stability, issues about cost and practical feasibility are concerned. An alternative approach is to intensify ion−solvent interactions in the inner solvation structure by shielding off outward electrostatic attractions from nearby ions. Here, we design an "overcrowded" electrolyte using the non-polar, hydrogen-bonding 1,4-dioxane (DX) as an overcrowding agent, thereby achieving a robust LiF-enriched SEI and wide electrolyte operation window (3.7 V) with a low salt concentration (<2 m). As a result, the electrochemical performance of aqueous Li 4 Ti 5 O 12 /LiMn 2 O 4 full cells can be substantially improved (88.5% capacity retention after 200 cycles, at 0.57 C). This study points out a promising strategy to develop low-cost and stable high-voltage aqueous batteries.

Alloy materials such as Si and Ge are attractive as high‐capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge–charge processes. Compared to the over‐emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid‐electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy‐based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF‐dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb‐coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g−1 after 200 cycles at 500 mA g−1, compared to only 72% and 170 mAh g−1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long‐term cycling stability for alloy‐based anode materials.

Alloy-based materials are promising anodes for rechargeable batteries because of their higher theoretical capacities in comparison to graphite. Unfortunately, the huge volume changes during cycling cause serious structural degradation and undesired parasitic reactions with electrolytes, resulting in fragile solid-electrolyte interphase formation and serious capacity decay. This work proposes to mitigate the volume changes and suppress the interfacial reactivity of Ge anodes without sacrificing the interfacial Li + transport, through in situ construction of an ultrarobust and lithiophilic Li-enriched Li−N nanoshield, which demonstrated improved chemical, electrochemical, mechanical, and environmental stability. Therefore, it can serve as a versatile interlayer to facilitate Li + transport and effectively block the attack of electrolyte solvents, thus boosting the long-term cycle stability and fast charging capability of Ge anodes. This work offers an alternative methodology to tune the interfaces of other electrode materials as well by screening for more N-containing compounds that can react with Li + during battery operation.