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There is a growing need for high energy, high power and safe lithium batteries for myriads of applications in powering microelectronic devices (such as smart cards, implantable medical devices, wearable electronics) to large power applications such as electric vehicles, aerospace and space equipments. One key requirement for such batteries is packing high energy in low form factor (i.e. thin-film form) to increase both the gravimetric and volumetric energy densities. Lithium superionic conducting solid ceramic electrolytes are the most prominent candidates amongst liquid, gel, polymer and solid ceramic electrolytes that can enable safety and optimum performance in a high energy density battery with thin-film cell components. For example, lithium aluminum germanium phosphate (LAGP) has been proven to be a promising solid-electrolyte due to its high ionic conductivity (~ 5 mS/cm at 23 °C), high electrochemical stability window (> 5V), and single Li+ ion conduction (high transference number, no dendrite formation, no crossover of electrode materials), thus enabling high energy battery chemistries and mitigating safety and packaging issues of conventional lithium batteries. However, application of solid-electrolyte (LAGP and others) in Li batteries is being hindered by lack of understanding of thin-film fabrication techniques/parameters, mechanical stability, and poor stability between solid ceramic electrolyte and electrodes, especially with Li metal anode. Low chemical stability between solid electrolyte and Li electrodes forms resistive interface (lower conductivity) which is detrimental for high power and cell longevity. We present materials and methods for electrolyte/electrode interface engineering that have shown promise but need further investigation. One such promising stable interface material is lithium phosphorus oxynitride (LiPON), when introduced as thin-film in between LAGP and Li reduces interface resistance (increase conductivity) considerably. Details on material’s thin-film fabrication techniques such as sputtering, physical vapor depositions, etc. and their resultant effects on solid-state battery performance will be presented.
Jitendra Kumar, Guru Subramanyam
Primary Advisor's Department
Applied Combustion and Energy
Stander Symposium project
"Study of Electrolyte/Electrodes Interface Engineering in Solid State Lithium-Ion Batteries" (2018). Stander Symposium Projects. 1181.