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At present, the most popular battery platform is the lithium-ion (Li-ion) battery. Li-ion batteries have high power density and lower memory effects compared to other battery compositions. With the never-ending dawn of more intricate, power hungry technologies, there is an increasing need for safe, smaller, more powerful and resilient batteries.
Thin film batteries appear to be the batteries of future technologies, as they are more fuel efficient, charge faster and hold a charge longer than conventional Li-ion batteries.
The layers that makeup the anode, cathode, and electrolyte in thin film batteries are micron-thick and are typically deposited using physical vapor deposition, either by thermal evaporation and sputtering.
The materials used to make the anode, cathode, and electrolyte of thin film batteries have been quickly progressing. Cathode materials tend to be intricate lithium-oxides like LiCoO2 and LiFePO4. Anode materials are normally made of carbon-based materials like graphite or lithium.
The majority of thin film battery applications are directed at improving current consumer and medical products. Thin film lithium ion batteries have been used to create thinner electronic devices, since the thickness of the battery is much less than that of conventional Li-ion batteries. Thin film batteries have particular promise for use in implantable medical devices, such as tiny defibrillators. These next-generation batteries can also be used in “smart” cards, radio frequency identification (RFID) tags and sensor devices. They also can be used to hold energy gathered from solar cells or other green technologies.
Thin film batteries have proven to be an effective storage device for energy gathered from solar and other green energy sources that have a varying generation rate. These batteries can be created to have a low self-discharge rate, meaning they can be kept for long intervals without a significant drop in stored energy. These fully-charged batteries could also potentially offer more dependable power to a smart electric grid.
Smart cards are similar in size to a standard credit card, but they include a microchip that can be used to get data, give data, provide authorization or process information. The fabrication processes used to make these cards involve rather harsh conditions, with temperatures reaching as high as 150 degrees Celsius. These conditions could cause other batteries to fail due to degassing or breakdown of the battery's components. However, thin film lithium ion batteries can tolerate temperatures between -40 to 150 degrees Celsius.
Incidentally, the robustness of thin film lithium ion batteries may be useful in other applications that involve temperatures the human body cannot tolerate.
Often associated with the Internet of Things (IoT), RFID tags are used in shipping and inventory control. RFID tags can be used for authentication, identification and security, among other things. Some RFID tags include sensor technology that is capable of detecting the surrounding physical environment.
The distance necessary to interact with the tag is determined by the strength of the battery: The stronger the output of the battery, farther away the RFID tag can be read. As these tags get more intricate, the battery demands will have to keep up, and thin film batteries can be incorporated into these tags thanks to the versatility of the battery with respect to size and shape, as well as the ability to power the functions of the tag. Low cost creation techniques of thin film batteries may even permit RFID technology to be used in disposable applications.
Medical devices that are implanted into the human body need batteries capable of providing a continuous, dependable power supply for as long as possible. These batteries must have a low self-discharge rate when not in use and a high power rate when it is being used, particularly for use in an implantable defibrillator. Batteries for implantable medical devices should also be able to go through a lot of charge-discharge cycles, so the devices do not have to frequently be replaced or serviced.
Thin film batteries are well-suited to meet the demands of implantable medical devices. Because thin film batteries have a solid electrolyte rather than a liquid electrolyte has allowed them to take countless forms without the issue of leakage, and it has been revealed that particular kinds of thin film batteries can last for approximately 50,000 cycles.