Xue Li

Lithium–sulfur batteries (LSBs) are recognized as one of the second-generation electrochemical energy storage systems with the most potential due to their high theoretical specific capacity of the sulfur cathode (1675 mAhg⁻¹), abundant elemental sulfur energy storage, low price, and green friendliness. However, the shuttle effect of polysulfides results in the passivation of the lithium metal anode, resulting in a decrease in battery capacity, Coulombic efficiency, and cycle stability, which seriously restricts the commercialization of LSBs. Starting from the separator layer before the positive sulfur cathode and lithium metal anode, introducing a barrier layer for the shuttle of polysulfides is considered an extremely effective research strategy. These research strategies are effective in alleviating the shuttle of polysulfide ions, improving the utilization of active materials, enhancing the battery cycle stability, and prolonging the cycle life. This paper reviews the research progress of the separator functionalization in LSBs in recent years and the research trend of separator functionalization in the future is predicted.

Lithium-ion batteries (LIBs) have been widely used in mobile devices, energy storage power stations, medical equipment, and other fields, became an indispensable technological product in modern society. However, the capacity degradation of LIBs limits their long-term deployment, which is not conducive to saving resources. What is more, it will lead to safety problems when the capacity of the battery is degraded. Failure of the battery is a key issue in the research and application of LIBs. Faced with the problem of capacity degradation, various aspects of LIBs have been studied. This paper reviews the electrochemical degradation mechanism of LIBs’ life fade, detection technologies for battery failure, methods to regulate battery capacity degradation, and battery lifetime prognostics. Finally, the development trend and potential challenges of battery capacity degradation research are prospected. All the key insights from this review are expected to advance the research on capacity fading and lifetime prediction techniques for LIBs.

There are many challenges for the Static lithium polysulfide semiliquid battery in its commercial application, such as poor stability of the cathode material and further amplification of the lithium polysulfide shuttle effect. Therefore, this manuscript introduced a new type of Pt₃Ni@C composite material as cathode working electrode based on the principle of volcanic catalytic curve. Through symmetric battery test, CV, polarization curves and impedance test, it was found that Pt₃Ni@C composite material had good catalytic activity of lithium polysulfide to improve electrochemical kinetics. When the catholyte was Li₂S₈ and the charge-discharge voltage range was 1.8~2.6 V, the capacity maintained at approximately 550 mAh g⁻¹, and the coulombic efficiency maintained at approximately 95% after 100 cycles at a current rate of 0.5 mA cm⁻². The Pt₃Ni@C composite material is a potential cathode material with the specific capacity and long cycling stability of the static lithium polysulfide semiliquid battery.

Lithium metal batteries have achieved large-scale application, but still have limitations such as poor safety performance and high cost, and limited lithium resources limit the production of lithium batteries. The construction of these devices is also hampered by limited lithium supplies. Therefore, it is particularly important to find alternative metals for lithium replacement. Sodium has the properties of rich in content, low cost and ability to provide high voltage, which makes it an ideal substitute for lithium. Sulfur-based materials have attributes of high energy density, high theoretical specific capacity and are easily oxidized. They may be used as cathodes matched with sodium anodes to form a sodium-sulfur battery. Traditional sodium-sulfur batteries are used at a temperature of about 300 °C. In order to solve problems associated with flammability, explosiveness and energy loss caused by high-temperature use conditions, most research is now focused on the development of room temperature sodium-sulfur batteries. Regardless of safety performance or energy storage performance, room temperature sodium-sulfur batteries have great potential as next-generation secondary batteries. This article summarizes the working principle and existing problems for room temperature sodium-sulfur battery, and summarizes the methods necessary to solve key scientific problems to improve the comprehensive energy storage performance of sodium-sulfur battery from four aspects: cathode, anode, electrolyte and separator.