APCT Technology

Key features of APCT Technology:

• novel organic electrolytes based on alkylamino phosphonium or alkylammonium salts and polar aprotic solvents 
• low-cost porous carbons as electrode materials and technology for purification of these carbons 
• special technique for electrode/electrolyte preparation together with some peculiarity of SC assembling and pre-starting (aging) procedure
• novel methods to significantly reduce ultracap inner resistance

Over the past decade or two ultracapacitors force their way to the market through the strong competition from advanced batteries. Today NiMH and in particular Li-ion batteries demonstrate the power density as high as 0.6-1 kW/kg (though at the expense of lower energy density, shorter cycle life and overheating). Therefore, to become competitive, ultracapacitors must demonstrate the power density much higher than 1 kW/kg providing at the same time the long cycle life. The best of our competitors and ultracapacitor manufacturers demonstrate 1-3 kW/kg at 95% efficiency, while our prototypes demonstrate 5-6 kW/kg.

Fig. 1  Comparison of APCT ultracapacitor power and energy density with major competitors:

Fig. 2  Ragone plot based on ITS test results presented at the Advanced Capacitor World Summit, San Diego in July 2008:

Fig. 3  Ragone plot (normalized) based on ITS test results presented at the Advanced Capacitor World Summit, San Diego in July 2008:

Another obstacle for ultracapacitors on the path to the market is cost of carbon. Nanoporous carbon, which is used as electrode material in supercapacitors, is rather expensive, and it typically contributes about 35% to the total cost. APCT has utilized carbon, which is 4 times cheaper than that used by its major competitors.

APCT middle and large devices can demonstrate the same performance being 2 or 3 times smaller (due to much higher power density), this means that APCT uses 2-3 times less material than competitors.

Currently, APCT research team is focused on achieving the following:

• to reduce ESR, in particular, to reduce the contact resistance at C/Al interface due to modification of Al current collector
• to modify some of the natural carbonaceous materials in order to produce low-cost nanoporous carbon electrodes
• to best match the electrode nanoporous texture with ion size in organic electrolytes
• to optimize the ratio between nanopores and ion transport channels in the electrode texture
• to optimize the electrode thickness
• to protect the Al current collector from anode corrosion
• to develop special fire retardant agents to assure safety