Boosting the Cycle Life of Li–O₂ Batteries at Elevated Temperature by Employing a Hybrid Polymer–Ceramic Solid Electrolyte

With the increasing demands of electric vehicle and grid storage, the solid-state Li–O₂ battery is generally considered as an alternative cost-effective energy-storage device because of its high energy density and safety. However, there are several challenges that need to be overcome to meet the stringent requirements imposed by diverse applications, especially at high temperature. In this work, an ion-conducting hybrid solid electrolyte (HSE) integrating polymer electrolyte with ceramic electrolyte (1:1 w/w) has been successfully designed and prepared, which displays high Li⁺ transference number (0.75) and ionic conductivity (0.32 mS cm^–1) at room temperature. The solid-state Li–O₂ battery enabled by the as-prepared HSE delivers a superior long life (350 cycles, >145 days) at 50 °C to that of the conventional ether-based nonaqueous Li–O₂ battery. The use of a HSE could lead to a new avenue for the development of high-performance solid-state Li–O₂ batteries

Novel Stable Gel Polymer Electrolyte: Toward a High Safety and Long Life Li–Air Battery

Nonaqueous Li–air battery, as a promising electrochemical energy storage device, has attracted substantial interest, while the safety issues derived from the intrinsic instability of organic liquid electrolytes may become a possible bottleneck for the future application of Li–air battery. Herein, through elaborate design, a novel stable composite gel polymer electrolyte is first proposed and explored for Li–air battery. By use of the composite gel polymer electrolyte, the Li–air polymer batteries composed of a lithium foil anode and Super P cathode are assembled and operated in ambient air and their cycling performance is evaluated. The batteries exhibit enhanced cycling stability and safety, where 100 cycles are achieved in ambient air at room temperature. The feasibility study demonstrates that the gel polymer electrolyte-based polymer Li–air battery is highly advantageous and could be used as a useful alternative strategy for the development of Li–air battery upon further application

Facile in Situ Preparation of Graphitic‑C₃N₄@carbon Paper As an Efficient Metal-Free Cathode for Nonaqueous Li–O₂ Battery

The rechargeable Li–O₂ batteries with high theoretical specific energy are considered to be a promising energy storage system for electric vehicle application. Because of the prohibitive cost, limited supply, and weak durability of precious metals, the developments of novel metal-free catalysts become significant. Herein, the graphitic-carbon nitride@carbon papers have been produced by a facile in situ method and explored as cathodes for Li–O₂ batteries, which manifest considerable electrocatalytic activity toward oxygen reduction reaction and oxygen evolution reaction in nonaqueous electrolytes because of their improved electronic conductivity and high nitrogen content. The assembled Li–O₂ batteries using graphitic-carbon nitride@carbon papers as cathodes deliver good rate capability and cycling stability with a capacity retention of more than 100 cycles

Integrated Design for Regulating the Interface of a Solid-State Lithium–Oxygen Battery with an Improved Electrochemical Performance

A composite solid-state electrolyte (SSE) with acceptable safety and durability is considered as a potential candidate for high-performance lithium–oxygen (Li–O2) batteries. Herein, to address the safety issues and improve the electrochemical performance of Li–O2 batteries, a solvent-free composite SSE is prepared based on the thermal initiation of poly(ethylene glycol) diacrylate radical polymerization, and an integrated battery is achieved by injecting an electrolyte precursor between electrodes during the assembly process through a simple heat treatment. The Li-metal symmetric cells based on this composite SSE achieve a critical current density of 0.8 mA cm–2 and a stable cycle life of over 900 h at a current density of 0.2 mA cm–2. This composite SSE effectively inhibits the erosion of O2 on the Li metal anode, optimizes the interface between the electrolyte and cathode, and provides abundant reaction sites for the electrochemical reactions during cycling. The integrated solid-state Li–O2 battery prepared in this work achieves stable long cycling (118 cycles) at a current density of 500 mA g–1 at room temperature, showing the promising future application prospects

Unraveling the Complex Role of Iodide Additives in Li–O₂ Batteries

Lithium iodide (LiI) has garnered considerable attention in aprotic Li–O₂ batteries. However, the reaction mechanism is still under hot debate and is attracting increasing controversy due to contrasting observations. Herein, on the basis of thorough evidence, a relevant mechanism has been systematically illustrated. LiI has been revealed to promote the superoxide-related nucleophilic attack toward electrolyte by catalyzing the decomposition of peroxide intermediate, resulting in the accumulation of LiOH and other parasitic products. Also, they refuse to be oxidized by not only triiodide (I₃^–) but also iodine (I₂), resulting in inevitable degradation. However, as a proton-donor, water can buffer the superoxide-related nucleophilic attack by reducing it to moderate hydroperoxide (HO₂^–). More importantly, the catalysis of iodide toward speroxide is restrained with the increase of alkalinity in water-contained electrolyte, resulting in the formation of Li₂O₂. Turning LiOH into Li₂O₂, the newly proposed mechanism leads to revolutionary reunderstanding toward the role of iodide and water in Li–O₂ battery systems