The proprietary doping method enables Li-ion capacitors (LiCs) to be manufactured at lower cost with generally available materials and equipment which are used for manufacturing lithium-ion batteries, says the company. At the same time, it enables the design and manufacture of capacitors with increased capacity and improved I/O performance.

Asahi Kasei developed a low-cost, pre-doping method using inexpensive lithium carbonate as the source of lithium ions, eliminating the need for perforated foil and lithium metal foil.  Lithium carbonate is included in the cathode and pre-doping is performed at initial charging, when nearly all of the lithium carbonate decomposes, and lithium ions transfer to the anode.  This allows the manufacture of LiCs using materials and equipment similar to those used in the manufacture of Li-ion batteries (LiBs), but also enables capacity and I/O performance to be raised by a factor of 1.3 or more (compared to Asahi Kasei's conventional LiCs).

The licensing includes Asahi Kasei's IP (intellectual property) related to LiC technology, but also technical expertise such as cell design and manufacturing with pilot equipment. Asahi Kasei expects to support licensees around the world to significantly reduce LiC development times and achieve low-cost LiC manufacture using existing equipment.

The LiC is a next generation energy storage device that uses the same material as an electric double layer capacitor (EDLC) for the cathode and the same material used as a LiB for the anode.  As LiCs have higher I/O characteristics than LiBs, they are suitable for where instantaneous power is needed, and can be quickly recharged.  The long cycle life and high safety LiCs are expected to be used in mobility applications such as electric trams and buses to charge at each stop instead of using power from overhead lines.

In the growing field of energy storage systems for renewable energy such as solar and wind, it is possible to extend the service life of LiBs by using with the LiCs to reduce the LiB charge/discharge load.  The company says this is expected to reduce both running costs and environmental impact through less frequent replacement of LiBs, generating less waste. The conventional LiC manufacturing process requires expensive materials for pre-doping, such as perforated foil and lithium metal foil.  In addition, lithium metal is highly reactive and hazardous, which incurs additional costs to maintain a safe working environment.