Lithium Titanate Anode Thin Films for Li-Ion Solid State Battery Based on Garnets

Solid state electrolytes, such as Li-Garnets, are fastest Li-ionic conductor materials that have attracted attention for safe hybrid and full solid state battery architectures. Turning to oxide-based low voltage anodes gives opportunities to avoid Li-dendrite formation and also to reach full thin film microbattery architectures based on garnets as high energy density replacement for supercapacitors. Herein, it is demonstrated that Li₄Ti₅O₁₂ thin films deposited by pulsed laser deposition can show stable structures and cycling kinetics reaching almost close to theoretical capacity of 175 mAh g⁻¹ when combined to Li_6.25Al_0.25La₃Zr₂O₁₂ pellets. Stable operation at room temperature with 90% of theoretical capacity retention at 2.5 mA g⁻¹ over 22 cycles is achieved on bilayer half cell batteries. Rate capability studies show promising charge and discharge capacities and act as a case study for the well-known Li₄Ti₅O₁₂ thin film anode, demonstrating its good compatibility with the investigated solid garnet electrolyte. This gives new perspective on the use of oxide-based low voltage anodes for future strategies avoiding Li-dendrite formation or safe solid state microbattery thin film assemblies based on Li-garnets.