Investigation of interfacial stability of Li1.3Al0.3Ti1.7(PO4)3 based all-solid-state lithium battery
The application of solid electrolyte instead of flammable liquid electrolyte can effectively solve the safety issues of lithium-ion batteries nowadays.However,the solid-solid contact of electrodes/electrolytes in solid state batteries usually lead to large interfacial impedance,resulting in high polarization.The polyvinylidene difluoride(PVDF)based solid electro-lyte was used as cathode and anode interface buffer layer,which effectively solved the problem of high impedance of tita-nium-aluminum-lithium phosphate solid electrolyte with electrode,reducing the positive interface impedance from 1716 Ω/cm2 to 213 Ω/cm2.At the anode interface,PVDF provided a good elastic support,so that the interfacial impedance was reduced from 1135 Ω/cm2 to 109 Ω/cm2.In addition,the direct current polarization of lithium symmetric battery showed that the stability of the anode interface was significantly improved after PVDF modification.Finally,the lithium co-balt oxide/lithium pouch battery was assembled.With PVDF modification on both cathode and anode interface,the energy density of the battery reached to 336 W·h/kg.The capacity retention rate was increased from 30.7%to 83.3%after 300 cycles at 1C.
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