Modification of sputter deposited solid-state electrolyte thin films

All solid-state thin film batteries (TFBs) consisting of amorphous lithium phosphorus oxynitride (LiPON) solid electrolyte, crystalline LiMn₂O₄ cathode and crystalline SnO₂ anode have been fabricated and characterized. All of the thin films are prepared by RF magnetron sputtering. By fabricating under different pressures and applying low temperature post-annealing (200 °C), the performances of the LiPON electrolytes and SnO₂/LiPON/LiMn₂O₄ TFBs are improved. Suitable working pressures results in pinhole-free amorphous LiPON films with smooth surface and dense micro-structure. The TFBs post-annealed at 200 °C show smooth interface contacts between electrode and electrolyte thin films. The low pressure deposited and post-annealed TFBs exhibits lower impedance and higher cycling stability. Initial open-circuit voltage of 3.8 V and initial capacity of 12 μAh/cm² are obtained.