Regulating electrochemical performances of lithium battery by external physical field

Lithium batteries have always played a key role in the field of new energy sources.However,non-controllable lithium dendrites and volume dilatation of metallic lithium in batteries with lithium metal as anodes have limited their development.Recently,a large number of studies have shown that the electrochemical performances of lithium batteries can be enhanced through the regulation of external physical fields.Especially,it significantly hinders the growth of lithium dendrites and promoting the reaction kinetics.This review summarizes recent innovations in the investigation of various physical fields of lithium batteries.The application of magnetic field in the synthesis of lithium battery electrode materials is introduced.The influence factors and regulation mechanism of various physical fields on the electrochemical performance of lithium batteries are reviewed emphatically.In addition,the current research status and existing challenges,along with future directions for the evolution of lithium batteries,are minutely discussed and prospected.New strategies for the further evolution of lithium batteries have also been provided.

Matched MnO@C anode and porous carbon cathode for Li-ion hybrid supercapacitors

Holding a promise of achieving high power and energy densities,Li-ion hybrid electrochemical capacitors present a crucial future direction for energy storage devices.However,technical challenges remain to appropriately couple both high-power capacitor-type and high-energy battery-type electrode materials within a same device.In addition,the current electrode materials in the device are usually prepared separately,which leads to lengthy preparation,time-consuming and high-cost.In this work,we report a simple method to prepare porous carbon materials(PC) with and without MnO nanoparticle cores,which function as very unique anode/cathode pairs for very high-performance Li ion hybrid supercapacitor.Taking the respective merits of high Li storage capacity from the MnO@C anode and high-rate performance from the PC cathode,the resulted device exhibits a remarkable energy density of 89 Wh·kg^(-1)(at 48 W·kg^(-1)) and can reach a battery-inaccessible power density of 18 kW·kg^(-1)(at 45Wh·kg^(-1)).

Pt and Te codoped ultrathin MoS_(2) nanosheets for enhanced hydrogen evolution reaction with wide pH range

Transition metal dichalcogenides,especially MoS_(2),have been examined as promising catalysts for hydrogen evolution reaction(HER).Meanwhile,MoS_(2)with various nanostructures and exposed more active sites has been broadly explored for boosting the HER performances at wide pH range.Here,a synergistic Pt and Te codoping strategy has been used to enhance the catalytic performance(including reducing the overpotential and promoting the HER reaction kinetics)of ultrathin MoS_(2)nanosheets in alkaline and acid electrolytes,which has delivered better than single Pt doping or single Te doping.

Nanoscratching and mechanical behaviors of high-entropy alloys with different phase constituents

High-entropy alloys(HEAs)exhibit unique microstructural features and properties in nanoscale and atomic scale because of their multi-element alloy system.The nanoscratching behaviors of three HEAs with different phase constituents,relative to the microstructure and mechanical properties of the HEAs,were investigated.Three typical phase constituents were selected:face-centered cubic(FCC)structure,body-centered cubic(BCC)structure,and a dual-phase structure containing both FCC and BCC phases.Despite the fact that the FCC alloy has the highest ductility and strain hardening capability,it exhibited inferior scratch resistance due to the over-softening of hardness.Due to the brittle failure mode,the BCC alloy hardly exhibited desirable scratch resistance despite its highest hardness.By contrast,the nanostructured dual-phase alloy exhibited the best scratch resistance because of its good combination of strength and ductility,as well as the ductile failure mode.This research suggests that the HEA with structure comprising nanoscale hard and soft phases is desirable for nanoscratch resistance,and possesses appropriate hardness for industrial applications.