Reduction of charge-transfer resistance at the solid electrolyte – electrode interface by pulsed laser deposition of films from a crystalline Li2PO2N source

• Amorphous films were deposited by PLD from crystalline Li2PO2N in N2.
• Films significantly improved charge-transfer resistance and CV profiles.
• Films show no evidence of planar PNPN backbone observed in the target.
• Using a crystalline Li2PO2N PLD target increases the ratio of N/P in the films.

Amorphous films deposited by pulsed laser deposition from a crystalline Li2PO2N target in a N2 ambient atmosphere (LiPON-PLD) have been examined as an approach to reduce the charge-transfer resistance at the electrode-solid electrolyte interface. Despite the relatively low ionic conductivity of ca. 1.5 × 10−8 S cm−1 at 25 °C, the amorphous LiPON-PLD films deposited between a LiMn1.485Ni0.45Cr0.05O4 (LNM) cathode and LiPON electrolyte resulted in sharply improved electrochemical performance in terms of charge-transfer resistance and CV profiles. Cells without a LiPON-PLD film had a charge-transfer resistance of 4470 Ω-cm2 compared to 760 and 960 Ω-cm2 for the sample with 17 nm and 31 nm thick LiPON-PLD films, respectively. The LiPON-PLD amorphous films show no evidence of the continuous planar PNPN- backbone characteristic of the crystalline target material, but compared with LiPON prepared from radio frequency magnetron sputtering with Li3PO4 in a N2 atmosphere, the LiPON-PLD films were composed of a higher amount of triply coordinated P−N