Lithium cation-doped tungsten oxide as a bidirectional nanocatalyst for lithium-sulfur batteries with high areal capacity

Lithium-sulfur(Li-S) batteries are promising for high energy-storage applications but suffer from sluggish conversion reaction kinetics and substantial lithium sulfide(Li_(2)S) oxidation barrier,especially under high sulfur loadings.Here,we report a Li cation-doped tungsten oxide(Li_(x)WO_(x)) electrocatalyst that efficiently accelerates the S■HLi_(2)S interconversion kinetics.The incorporation of Li dopants into WO_(x) cationic vacancies enables bidirectional electrocatalytic activity for both polysulfide reduction and Li_(2)S oxidation,along with enhanced Li^(+) diffusion.In conjunction with theoretical calculations,it is discovered that the improved electrocatalytic activity originates from the Li dopant-induced geometric and electronic structural optimization of the Li_(x)WO_(x),which promotes the anchoring of sulfur species at favourable adsorption sites while facilitating the charge transfer kinetics.Consequently,Li-S cells with the Li_(x)WO_(x) bidirectional electrocatalyst show stable cycling performance and high sulfur utilization under high sulfur loadings.Our approach provides insights into cation engineering as an effective electrocatalyst design strategy for advancing high-performance Li-S batteries.

Rapid photothermal heating of aqueous batteries for lowtemperature conditions

Aqueous batteries are promising for large-scale applications owing to their affordability,eco-friendliness,and nonflammability.However,their usability in cold regions is limited by electrolyte freezing and slow ion-transfer kinetics at subzero temperatures.This study demonstrates the stable operation of aqueous batteries in subzero conditions by integrating high-efficiency photothermal current collectors with suspension electrodes.The Ketjen black-based photothermal current collectors efficiently convert a broad spectrum of sunlight(98%,200-2500 nm)into thermal energy,enabling rapid heat generation.Simultaneously,the high thermal conductivity of the suspension electrode ensures quick distribution of thermal energy throughout the battery.This configuration allows the cell’s core temperature to rapidly increase from-18℃to 20℃within 22 min under simulated solar irradiation.Additionally,an integrated light concentrator and temperature regulation system has been developed to improve heating rates and ensure the temperature stability of the cell under various climatic conditions.As a result,the cell can maintain a stable temperature of 20℃during consecutive charge/discharge cycles,even with an ambient temperature fluctuating between-5℃and 5℃.This integrated photothermal battery design exhibits great potential for cold weather conditions,paving the way for the deployment of large-scale aqueous battery systems in polar regions.

Graphene oxide:An emerging electromaterial for energy storage and conversion

This paper gives a comprehensive review of the recent progress on electrochemical energy storage devices using graphene oxide(GO).GO,a single sheet of graphite oxide,is a functionalised graphene,carrying many oxygen-containing groups.This endows GO with various unique features for versatile applications in batteries,capacitors and fuel cells.Specific applications are considered principally including use in electrodes as the active materials to enhance the performance or as substrates to diversify the structures,in solid-state electrolytes and membranes to improve the ionic conductivity and mechanical properties,and in interlayers to protect the electrodes,membranes or current collectors.Furthermore,the challenges and future prospects are discussed in the paper for encouraging further research and development of GO applications.