"Lithium-free" Thin Film Batteries

The "Li-free" thin film batteries are fabricated with only an anode current collector and the protective overlayer. Upon the initial charge of the battery, a metallic lithium anode is plated in-situ at the current collector. This lithium anode can be plated and stripped reversibly.

Features:

• The capacity and discharge rates are as high as batteries with an evaporated Li anode.
• The cells can be cycled thousands of times.
• The newly fabricated battery can be heated to 250°C.

NOTE: Failure due to a significant internal leakage current occurs for about 25% of the Li-free batteries fabricated in our laboratory, while for the evaporated lithium anode batteries the failure rate is < 10%. Changes in the materials and processing may be needed to improve the fabrication yield.

Discharge curves for batteries with a 1.8 µm x 1 cm² LiCoO₂ cathode.

Discharge capacity of Li-free batteries with and without a protective overlayer coating. Capacities are normalized to a 1 cm² x 1 µm thick LiCoO₂ cathode.