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Uncontrollable zinc (Zn) plating and hydrogen evolution greatly undermine Zn anode reversibility. Previous electrolyte designs focus on suppressing H2O reactivity, however, the accumulation of alkaline byproducts during battery calendar aging and cycling still deteriorates the battery performance. Here, we present a direct strategy to tackle such problems using a strong Brønsted acid, bis(trifluoromethanesulfonyl)imide (HTFSI), as the electrolyte additive. This approach reformulates battery interfacial chemistry on both electrodes, suppresses continuous corrosion reactions and promotes uniform Zn deposition. The enrichment of hydrophobic TFSI– anions at the Zn|electrolyte interface creates an H2O-deficient micro-environment, thus inhibiting Zn corrosion reactions and inducing a ZnS-rich interphase. This highly acidic electrolyte demonstrates high Zn plating/stripping Coulombic efficiency up to 99.7% at 1 mA cm–2 (> 99.8% under higher current density and areal capacity). Additionally, Zn | |ZnV6O9 full cells exhibit a high capacity retention of 76.8% after 2000 cycles. Trace amounts of strong acid can suppress Zn corrosion and promote uniform Zn deposition. Here, the authors use HTFSI to create a hydrophobic micro-environment at the Zn-electrolyte interface, enabling high efficiency and cycling stability. [ABSTRACT FROM AUTHOR]

The stable cycling of Mg‐metal anodes is limited by several problems, including sluggish electrochemical kinetics and passivation at the Mg surface. In this study, we present a high‐entropy electrolyte composed of lithium triflate (LiOTf) and trimethyl phosphate (TMP) co‐added to magnesium bis(trifluoromethane sulfonyl)imide (Mg(TFSI)2/1,2‐dimethoxyethane (DME) to significantly improve the electrochemical performance of Mg‐metal anodes. The as‐formed high‐entropy Mg2+‐2DME‐OTf−‐Li+‐DME‐TMP solvation structure effectively reduced the Mg2+‐DME interaction in comparison with that observed in traditional Mg(TFSI)2/DME electrolytes, thereby preventing the formation of insulating components on the Mg‐metal anode and promoting its electrochemical kinetics and cycling stability. Comprehensive characterization revealed that the high‐entropy solvation structure brought OTf− and TMP to the surface of the Mg‐metal anode and promoted the formation of a Mg3(PO4)2‐rich interfacial layer, which is beneficial for enhancing Mg2+ conductivity. Consequently, the Mg‐metal anode achieved excellent reversibility with a high Coulombic efficiency of 98 % and low voltage hysteresis. This study provides new insights into the design of electrolytes for Mg‐metal batteries. [ABSTRACT FROM AUTHOR]

Electrolyte freezing under low temperatures is a critical challenge for the development of aqueous batteries (ABs). While lowering the freezing point of the electrolyte has caught major research efforts, limited attention has been paid to the structural evolution during the electrolyte freezing process and regulating the frozen electrolyte structure for low temperature ABs. Here, we reveal the formation process of interconnected liquid regions for ion transport in frozen electrolytes with various in situ variable‐temperature technologies. More importantly, the low‐temperature performance of ABs was significantly improved with the colloidal electrolyte design using graphene oxide quantum dots (GOQDs), which effectively inhibits the growth of ice crystals and expands the interconnected liquid regions for facial ion transport. This work provides new insights and a promising strategy for the electrolyte design of low‐temperature ABs. [ABSTRACT FROM AUTHOR]

The issues of inherent low anodic stability and high flammability hinder the deployment of the ether‐based electrolytes in practical high‐voltage lithium metal batteries. Here, we report a rationally designed ether‐based electrolyte with chlorine functionality on ether molecular structure to address these critical challenges. The chloroether‐based electrolyte demonstrates a high Li Coulombic efficiency of 99.2 % and a high capacity retention >88 % over 200 cycles for Ni‐rich cathodes at an ultrahigh cut‐off voltage of 4.6 V (stable even up to 4.7 V). The chloroether‐based electrolyte not only greatly improves electrochemical stabilities of Ni‐rich cathodes under ultrahigh voltages with interphases riched in LiF and LiCl, but possesses the intrinsic nonflammable safety feature owing to the flame‐retarding ability of chlorine functional groups. This study offers a new approach to enable ether‐based electrolytes for high energy density, long‐life and safe Li metal batteries. [ABSTRACT FROM AUTHOR]