Synergistic Fe−Se Atom Pairs as Bifunctional Oxygen Electrocatalysts Boost Low-Temperature Rechargeable Zn-Air Battery

Herein, we successfully construct bifunctional electrocatalysts by synthesizing atomically dispersed Fe−Se atom pairs supported on N-doped carbon (Fe−Se/NC). The obtained Fe−Se/NC shows a noteworthy bifunctional oxygen catalytic performance with a low potential difference of 0.698 V, far superior to that of reported Fe-based single-atom catalysts. The theoretical calculations reveal that p-d orbital hybridization around the Fe−Se atom pairs leads to remarkably asymmetrical polarized charge distributions. Fe−Se/NC based solid-state rechargeable Zn-air batteries (ZABs−Fe−Se/NC) present stable charge/discharge of 200 h (1090 cycles) at 20 mA cm⁻² at 25 °C, which is 6.9 times of ZABs−Pt/C+Ir/C. At extremely low temperature of −40 °C, ZABs−Fe−Se/NC displays an ultra-robust cycling performance of 741 h (4041 cycles) at 1 mA cm⁻², which is about 11.7 times of ZABs−Pt/C+Ir/C. More importantly, ZABs−Fe−Se/NC could be operated for 133 h (725 cycles) even at 5 mA cm⁻² at −40 °C.     

Revealing the Interfacial Chemistry of Fluoride Alkyl Magnesium Salts in Magnesium Metal Batteries

Exploring promising electrolyte-system with high reversible Mg plating/stripping and excellent stability is essential for rechargeable magnesium batteries (RMBs). Fluoride alkyl magnesium salts (Mg(OR^F)₂) not only possess high solubility in ether solvents but also compatible with Mg metal anode, thus holding a vast application prospect. Herein, a series of diverse Mg(OR^F)₂ were synthesized, among them, perfluoro-tert-butanol magnesium (Mg(PFTB)₂)/AlCl₃/MgCl₂ based electrolyte demonstrates highest oxidation stability, and promotes the in situ formation of robust solid electrolyte interface. Consequently, the fabricated symmetric cell sustains a long-term cycling over 2000 h, and the asymmetric cell exhibits a stable Coulombic efficiency of 99.5 % over 3000 cycles. Furthermore, the Mg||Mo₆S₈ full cell maintains a stable cycling over 500 cycles. This work presents guidance for understanding structure–property relationships and electrolyte applications of fluoride alkyl magnesium salts.     

Composing atomic transition metal sites for high-performance bifunctional oxygen electrocatalysis in rechargeable zinc–air batteries

Rechargeable zinc–air batteries have attracted extensive attention as clean, safe, and high-efficient energy storage devices. However, the oxygen redox reactions at cathode are highly sluggish in kinetics and severely limit the actual battery performance. Atomic transition metal sites demonstrate high electrocatalytic activity towards respective oxygen reduction and evolution, while high bifunctional electrocatalytic activity is seldomly achieved. Herein a strategy of composing atomic transition metal sites is proposed to fabricate high active bifunctional oxygen electrocatalysts and high-performance rechargeable zinc–air batteries. Concretely, atomic Fe and Ni sites are composed based on their respective high electrocatalytic activity on oxygen reduction and evolution. The composite electrocatalyst demonstrates high bifunctional electrocatalytic activity (ΔE = 0.72 V) and exceeds noble-metal-based Pt/C + Ir/C (ΔE = 0.79 V). Accordingly, rechargeable zinc–air batteries with the composite electrocatalyst realize over 100 stable cycles at 25 mA cm⁻². This work affords an effective strategy to fabricate bifunctional oxygen electrocatalysts for high-performance rechargeable zinc–air batteries.     

Toward Sustainable Metal-Iodine Batteries: Materials,Electrochemistry and Design Strategies

Due to the natural abundance of iodine, cost-effective, and sustainability, metal-iodine batteries are competitive for the next-generation energy storage systems with high energy density, and large power density. However, the inherent properties of iodine such as electronic insulation and shuttle behavior of soluble iodine species affect negatively rate performance, cyclability, and self-discharge behavior of metal-iodine batteries, while the dendrite growth and metal corrosion on the anode side brings potential safety hazards and inferior durability. These problems of metal-iodine system still exist and need to be solved urgently. Herein, we summarize the research progress of metal-iodine batteries in the past decades. Firstly, the classification, design strategy and reaction mechanism of iodine electrode are briefly outlined. Secondly, the current development and protection strategy of conventional metal anodes in metal-iodine batteries are highlighted, and some potential anode materials and their design strategies are proposed. Thirdly, the key electrochemical parameters of state-of-art metal-iodine batteries are compared and analyzed to solve critical issues for realizing next-generation iodine-based energy storage systems. Therefore, the aim of this review is to promote the development of metal-iodine batteries and provide guidelines for their design.     

40 Years of Low-Temperature Electrolytes for Rechargeable Lithium Batteries

Rechargeable lithium batteries are one of the most appropriate energy storage systems in our electrified society, as virtually all portable electronic devices and electric vehicles today rely on the chemical energy stored in them. However, sub-zero Celsius operation, especially below −20 °C, remains a huge challenge for lithium batteries and greatly limits their application in extreme environments. Slow Li⁺ diffusion and charge transfer kinetics have been identified as two main origins of the poor performance of RLBs under low-temperature conditions, both strongly associated with the liquid electrolyte that governs bulk and interfacial ion transport. In this review, we first analyze the low-temperature kinetic behavior and failure mechanism of lithium batteries from an electrolyte standpoint. We next trace the history of low-temperature electrolytes in the past 40 years (1983–2022), followed by a comprehensive summary of the research progress as well as introducing the state-of-the-art characterization and computational methods for revealing their underlying mechanisms. Finally, we provide some perspectives on future research of low-temperature electrolytes with particular emphasis on mechanism analysis and practical application.