Ionic Capacitors

'Ionic Capacitor', is an umbrella term for a range of electrochemical energy storage devices, i.e. batteries. A device is designated 'ionic capacitor' if some, or all of the energy stored is held through the + - interaction of a charged electrode and its oppositely charged ion.

  • Supercapacitor (EDLC)

    The EDLC or 'electric double layer capacitor' is a device which utilises a very high surface area 'activated' carbon for both the anode and cathode.

    An electrolyte, comprising both +ve and 've ions, is mobile throughout the cell and when charged, the +ve ions migrate to the -ve electrode and the -ve ions migrate to the +ve electrode.

    The energy is related to the voltage of the cell and the capacitance of the specific carbon with specific electrolte.s

  • AR.Ion / Lithium Ion Capacitor

    These devices trade one of the electrodes in an EDLC for 'battery' type materials. The trade off is lower power, efficiency and cycle life for increased energy density and a lower cost/kWh.

Allotrope Energy's Capacitors

Using a unique combination of high surface area carbon and advanced electrolytes, Allotrope Energy has developed some of the highest performing capacitors in the world.

High energy supercapacitors look to tailor the cell's components for the highest Wh/kg achievable.

The energy density of the EDLC of often cited, along with cost, as being the major bottleneck for increased adoption. Developed in part through an InnovateUK grant, Allotrope has developed the following cell.

Parameter Value Units
Energy Density 10-20 Wh/kg
Power Density 5-10 kW/kg
Efficiency 97 %
Volumetric Density 35 Wh/l
Cycle Life > 1M

In contrast to high energy EDLCs the high power concentrates on minimising the various resistances which limit pulse power performance. With some of the lowest resistances available, the Allotrope high power cells can charge and discharge at class-leading powers.

With charging powers some 1000x that of a common lithium ion battery, the high power EDLC is a remarkable device.

Parameter Value Units
Energy Density 5-10 Wh/kg
Power Density 25-50 kW/kg
Efficiency 98 %
Volumetric Density 20 Wh/l
Cycle Life > 1M

AR.Ion is one of the most exciting new battery technologies. Formed from two new complimentary materials, the AR.Ion truly fills the void between lithium ion batteries and supercapacitors, both of which represent state-of-the-art

In much the same way as the EDLC, the AR.Ion cell can be tailored for maximum energy density, maximum power density or a combination of the two.

Parameter Value Units
Energy Density 50 Wh/kg
Power Density 5-10kW kW/kg
Efficiency >90 %
Volumetric Density 90 Wh/l
Cycle Life >100K

The high power AR.Ion cell is an incredibly versatile device whose unmatched ability to transfer energy at high efficiencies makes it an optimal choice for performance electro-mechanical systems.

Parameter Value Units
Energy Density 20-30 Wh/kg
Power Density >10 kW/kg
Efficiency 94 %
Volumetric Density 60 Wh/l
Cycle Life >100K

"Allotrope ionic capacitors represent a major opportunity for high performance systems" - Chris Ellis (CTex)