The GC Lithium-ion Capacitor features the highest energy density of any commercial supercapacitor

 

 

 

What is a Lithium-ion Capacitor?

The Lithium-ion Capacitor is an electrochemical capacitor that combines the ion intercalation mechanism of a lithium-ion battery with the cathode composition of an electric double-layer capacitor, commonly known as a supercapacitor or ultracapacitor. This hybrid configuration allows the LiC to have superior energy density compared to conventional supercapacitors and increased power density, safety, and charging efficiency compared to lithium-ion batteries. 

 

The graphic above shows the basic structure of the LIC cell. Three main components include: positive activated carbon cathodes, negative pre-lithiated anodes, and separator membrane.

 

Batteries, supercapacitors (also known as EDLCs), and LiCs all have unique properties which make them suitable for specific applications. The LiC has higher power, longer cycle life, and are safer to use than batteries. LiCs also have a higher voltage and much more energy density than EDLCs. Since LiCs combine both high energy density and high power density, they can improve efficiency and enhance power of electrical systems by replacing existing energy storage technologies, including both EDLCs and batteries.

Above graph shows the cycling performance of the LIC 200F cell charging at 4 A. 

 

The unique configuration of the LiC cell is comprised of activated carbon cathodes and graphitic anodes that are pre-lithiated by a patented process. The lithiated anode lowers the charge potential which results in an overall higher cell voltage. The GC Li-ion Capacitor utilizes specially-developed high-performance carbon electrodes that increase capacity and lower internal resistance. Further, due to a proprietary process, GC LiCs have a lower cost of production compared to conventional supercapacitor technology.

 
 

The Ragone chart above shows different types of energy storage devices and their relative energy and power densities. This chart represents how the properties of the Lithium-Ion Capacitor bridge the gap between batteries and capacitors.

 

Rechargeable batteries aren't as efficient as LiCs for delivering large loads because when fully discharged, a "memory effect" occurs that quickly diminishes the battery's capacity over time. Thus, most batteries can only perform around 500-1000 charge cycles before they become depleted- this is why a car or cell phone battery must be replaced every few years. However, the GC LiC can perform over 300,000 charge-discharge cycles. This equals many more years of operation, requires less maintenance, and greatly reduces cost of ownership.

 

 

GC Li-ion Capacitor cells are tested for capacitance, internal resistance, cycle life, and temperature range using the same performance metrics as established by industry-leading supercapacitor manufacturers. This includes the high temperature, high voltage DC-life test. In this test, the cell is kept at 3.8 V floating voltage for over 2000 continuous hours in a 65° C heat environment and must retain over 80% of initial capacitance.

LiCs are also tested for self-discharge- averaging only a 5% voltage drop from maximum charge over a three month period. Compare that to EDLC-type supercapacitors- which can lose up to 50% of charge within a single month.