Class of thin film cathodes based on the solid solution of two layered lithium metal oxide components


With the continued evolution of microelectronic devices and their miniaturization, there is significant demand for energy storage devices with reduced dimensions, especially lithium-ion batteries. Solid-state lithium thin-film batteries (TFB’s) possess exceptional energy storage performance with long cycle life, enhanced safety, and high specific energies. They have been developed over several decades for a range of applications, including distributed sensors, memory backup on microchips, etc. The cell components in TFB’s are fabricated as thin dense films supported on a macroscopically thick substrate using vacuum deposition techniques including thermal evaporation, sputtering, and pulsed laser deposition Thin-film cathode materials with much higher specific capacities are needed as they constrain the overall energy density of the thin film battery. These cathode films are typically polycrystalline and require high temperature (>500 °C) annealing to achieve optimal energy storage performance, which can significantly increase production cost and limit the choice of compatible substrate materials.

Technology Overview

The university has invented a high-capacity thin-film cathode for thin film lithium micro-batteries. The cathode is shown to be fully functional and reversible in the as-deposited, unannealed state; it does not require high temperature processing. Though prepared by RF magnetron sputtering in the original demonstration, these cathodes may be prepared using alternative deposition techniques, such as chemical vapor deposition, plasma-enhanced chemical vapor deposition, thermal evaporation, electron-beam evaporation, and the like.


The as-deposited thin-film cathode has a stable capacity that is 50% greater than the discharge capacity of the state-of-the-art thin-film cathode (210 mAh g-1 vs. 110 mAh g-1 for thin film polycrystalline LiCoO2.) It can be cycled reversibly over hundreds of cycles, with more than 90% capacity retention over 175 cycles. Because thermal annealing is not required, the cathode film and entire thin film battery can be prepared on low-cost, commodity thermoplastic substrates. Cycled over 120 charge/discharge cycles, the cathode averages a coulombic efficiency of 97.5% on a thermoplastic substrate in a curved conformation. Further enhancement of electrochemical performance (thousands of cycles and coulombic efficiency of >99%) is expected through optimization of the thin film battery structure and testing conditions/atmosphere. Owing to the employment of flexible low-cost polymer substrates, our high-capacity and flexible thin film battery is an excellent energy storage solution for flexible microelectronics.


Thin film lithium batteries

URV Reference Number: 2-21072
Patent Information:
For Information, Contact:
McKenna Geiger
Licensing Manager
University of Rochester
Wyatt Tenhaeff
Fei Hu
William West