Enhancing the reversible capacity and cycle stability of lithium-ion batteries with Li-compensation material Li_(6)CoO_(4)

High-capacity anode materials,such as SiO and Si/C,are considered promising candidates for high-energydensity lithium-ion batteries.However,the low initial Coulombic efficiency of these anode materials induced by side reactions(forming Li_(2)O and lithium silicate)and the formation of solid electrolyte interface film reduces the active Liions and causes low-discharge capacity.Adding a Li-compensation material in the cathode or anode is an effective strategy to overcome this problem.The most used Li-compensation material is the stabilized lithium metal powder.However,this strategy has high safety risks,high costs,and is challenging to quantify.Herein,the Li-compensation material of Li_(6)CoO_(4) is synthesized and investigated.The preparation conditions,stability in the air,delithiation mechanism,and structural transformation are analyzed and discussed.Electrochemical tests reveal that the discharge capacity and capacity retention of the full pouch cells(3-Ah)with Li_(6)CoO_(4) additive is significantly improved.Also,the reason for such improvement is investigated.This work provides an effective strategy of Li-compensating technology to enhance the electrochemical performance of lithium-ion batteries.

Surface Coating Enabling Sulfide Solid Electrolytes with Excellent Air Stability and Lithium Compatibility

All-solid-state lithium metal batteries(ASSLMBs)featuring sulfide solid electrolytes(SEs)are recognized as the most promising next-generation energy storage technology because of their exceptional safety and much-improved energy density.However,lithium dendrite growth in sulfide SEs and their poor air stability have posed significant obstacles to the advancement of sulfide-based ASSLMBs.Here,a thin layer(approximately 5 nm)of g-C_(3)N_(4)is coated on the surface of a sulfide SE(Li_(6)PS_(5)Cl),which not only lowers the electronic conductivity of Li_(6)PS_(5)Cl but also achieves remarkable interface stability by facilitating the in situ formation of ion-conductive Li3N at the Li/Li_(6)PS_(5)Cl interface.Additionally,the g-C_(3)N_(4)coating on the surface can substantially reduce the formation of H_(2)S when Li_(6)PS_(5)Cl is exposed to humid air.As a result,Li-Li symmetrical cells using g-C_(3)N_(4)-coated Li_(6)PS_(5)Cl stably cycle for 1000 h with a current density of 0.2 mA cm^(-2).ASSLMBs paired with LiNbO_(3)-coated LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2)exhibit a capacity of 132.8 mAh g^(-1)at 0.1 C and a high-capacity retention of 99.1%after 200 cycles.Furthermore,g-C_(3)N_(4)-coated Li_(6)PS_(5)Cl effectively mitigates the self-discharge behavior observed in ASSLMBs.This surface-coating approach for sulfide solid electrolytes opens the door to the practical implementation of sulfide-based ASSLMBs.

Surface modification of Li_(3)InCl_(6)provides superior electrochemical performance for LiMn_(2)O_(4)cathode materials

Li Mn_(2)O_(4)(LMO)is the substance of choice for small and medium-sized energy storage materials in daily life.In this work,Li3InCl6(LIC)is prepared on the surface of LiMn_(2)O_(4)by hydrothermal method using InCl_(3)and LiCl as raw materials.This method stabilizes the LMO crystal structure by uniformly coating the LIC on the LMO surface and effectively maintains the morphology of LMO crystals during the cycling process.SEM and EDS analysis confirm the morphology and homogeneity of the synthesized material LIC on the LMO surface.The prepared material is put into a battery,and the charge-discharge test is carried out at 0.5 C and 1 C.The results show that the LIC surface-modified samples exhibit more than 6%higher cycling performance than the unmodified samples after long cycling.