Research On Improving Interface Properties By Femtosecond Laser Structuring On Solid State Electrolyte LAGP

The research and development of lithium ion secondary battery has promoted the popularization of portable mobile devices and transportation vehicles.The research on all-solid-state lithium metal batteries with high volume density,high power density and high-security has bright future in daily life.The organic liquid electrolyte or polymer electrolyte used in traditional lithium-ion secondary battery has potential safety hazards due to leakage and thermal instability,which has always been a key problem to be solved.As an important part of all solid state battery.Among all kinds of solid-state electrolytes,NASICON solid-state electrolyte Li1.5Al0.5Ge1.5(PO4)3(LAGP)has the advantages of high ionic conductivity at room temperature,good stability in atmospheric environment,wide electrochemical window and so on.The whole battery assembled by NASICON is expected to fundamentally solve the above problems and has become a research hotspot in recent years.However,solid/solid contact between LAGP and electrode leads to poor interface wettability,and large are specific impedance leads to unsatisfactory electrochemical performance of the all-solid-state cells.Improving the interfacial performance of electrode/solid electrolyte by interfacial modification has become a research hotspot in the field of all-solid-state battery.Improving the interface performance of electrode/LAGP through interface modification has become a research hotspot in the field of all-solid-state-battery.This paper proposes to design and prepare surface texture on the surface of solid electrolyte,and fill ionic liquid forming composite electrolyte to improve the wettability of interface and the electrochemical performance of all-solid-state lithium battery.The specific research contents are as follows:(1)The effect of femtosecond laser etching parameters on the surface morphology of LAGP solid electrolyte with wavelength 228 fs was investigated,and the processing parameters were optimized.The results show that the influence of femtosecond laser processing on the surface grain integrity of LAGP solid electrolyte can be reduced by femtosecond laser processing power of 1.5W,processing speed of20mm/s and scanning times of 5 times.(2)The textured surface can improve the surface wettability of solid-state electrolyte and has high capacity retention rate.In a typical surface texture,the interfacial area specific impedance is 9.4Ω cm-2when the grid texture spacing is40μm,and the capacity retention rate is 90.7% after 50 cycles at rate of 0.2C.Bionic texture can greatly improve the wettability of solid electrolyte and regulate the process of lithium ion deposition/stripping.The lithium metal symmetry battery with texture surface texture bionic dragonfly wings can maintain a relatively stable over-potential of 50 m V for 1400 h without failure.