Thin-film lithium-ion battery

Metal oxide materials are shown below as well as their relative specific capacities (Λ), open circuit voltages (Voc), and energy densities (DE).

The concept of thin-film lithium-ion batteries was increasingly motivated by manufacturing advantages presented by the polymer technology for their use as electrolytes.

[6] Solid polymer electrolytes offer several advantages in comparison to a classical liquid lithium-ion battery.

Silver nanowires with improved surface area and loading weight have been shown to work as a current collector in these battery systems, but still are not as cost-effective as desired.

Extending graphite technology to lithium-ion batteries, solution processed carbon nanotubes (CNT) films are being looked into for use as both the current collector and anode material.

CNTs have the ability to intercalate lithium and maintain high operating voltages, all with low mass loading and flexibility.

Thin-film lithium-ion batteries offer improved performance by having a higher average output voltage, lighter weights thus higher energy density (3x), and longer cycling life (1200 cycles without degradation) and can work in a wider range of temperatures (between -20 and 60 °C)than typical rechargeable lithium-ion batteries.

In the thin-film lithium-ion battery, both electrodes are capable of reversible lithium insertion, thus forming a Li-ion transfer cell.

Also liquid electrolytes in general call for an increase in the overall volume of the battery, which is not ideal for designing a system that has high energy density.

Finally, solid systems can be packed together tightly which affords an increase in energy density when compared to classical liquid lithium-ion batteries.

These batteries have the ability to be an integral part of implantable medical devices, such as defibrillators and neural stimulators, “smart” cards,[8] radio frequency identification tags[3] and wireless sensors.

The thin-film lithium-ion battery can serve as a storage device for the energy collected from renewable sources with a variable generation rate, such as a solar cell or wind turbine.

These ID tags can even have other integrated sensors to allow for the physical environment to be monitored, such as temperature or shock during travel or shipping.

[3] Thin films of LiCoO2 have been synthesized in which the strongest X-ray reflection is either weak or missing, indicating a high degree of preferred orientation.

The reliability and performance of Li LiCoO2 thin-film batteries make them attractive for application in implantable devices such as neural stimulators, pacemakers, and defibrillators.

Implantable medical devices require batteries that can deliver a steady, reliable power source for as long as possible.

Wireless sensors need to be in use for the duration of their application, whether that may be in package shipping or in the detection of some unwanted compound, or controlling inventory in a warehouse.

If the wireless sensor cannot transmit its data due to low or no battery power, the consequences could potentially be severe based on the application.

This means that the desired battery for these devices must be long-lasting, size specific, low cost, if they are going to be used in disposable technologies, and must meet the requirements of the data collection and transmission processes.