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Advanced super capacitor-based storage

Batteries, Chemical, Supercapacitors

Comparing Supercapacitor Technology to Lithium Ion Batteries

rechargeable-lithium-ion-battery

The Kilowatt Lab SuperCap Energy Storage unit is made up of dozens of small supercapacitors with a combined 3.55kWh of energy storage in each unit – so, the internal structure isn’t much different than a lithium battery pack built by Tesla. Tesla uses dozens of small lithium battery cells to create their final unit energy storage but, what is different is the way a super capacitor manages electricity vs a chemical battery.

In the broad definition of batteries and energy storage, capacitors store energy, so they are batteries.  But the process of energy storage in batteries and in capacitors is fundamentally different.  Batteries use different materials for the cathode (-) and the anode (+). Batteries chemically change at an atomic level as electrons are released and molecules are exchanged in the oxidation-reduction (redox) process from the anode to the cathode (discharge) through the electrolyte.

Capacitors use the same electrode material on each and rely on electrostatic charge on one plate to produce a voltage differential between the two plates.  Energy density of a capacitor is a function of the surface area of the plates. An electrolytic capacitor, commonly found in electronics has simple metal or foil plates with a dielectric separator in between.  Super capacitors are unique among capacitors with the addition of a conductive material to absorb more electrons on the anode plate, and thereby functionally increasing the surface area and thus, their energy density.

In the SuperCap Energy Storage super capacitor, kW Labs uses 94% graphene with 6% lithium doping (Diffuse layer) and an insulating polymer (Separator) as the dielectric material between the two plates. KiloWatt Labs has determined that this ratio of graphene to lithium optimizes the plate’s ability to store electrons and therefore optimizes its energy density.

To put this in perspective, the theoretical charge level of lithium metal in a chemical battery is 3.8Ah/gram. A cell with nominal voltage of 3.6V would produce 13.68 Wh. So, in theory, 1 kWh of energy storage would require 73 grams of Lithium metal. In practice, this quantity is 4-5 times greater due to several factors. When lithium is used to increase the capacitive charge capability of a super capacitor, the Lithium metal content required drops to less than 5 milligrams of Lithium metal to achieve similar energy density.

Because capacitors do not rely on a chemical redox process, there is no possibility of the thermal runaway that exists in a chemical battery. Furthermore, the primary material used in creating increased energy density in a SuperCap super capacitor is graphene which is an inherently stable carbon structure.

Lithium-based batteries have limited lifetime cycles due to parasitic reactions that occur every time the battery is discharged and recharged. If kept in a 100% charged state, this parasitic reaction increases, further decaying the battery life. Super capacitors achieve 100X the cycle life of a lithium battery because there is no such reaction in the capacitor discharge/charge process. Since the parasitic reaction does not exist, super capacitors can be kept at 100% charge indefinitely with no degradation of life.

 

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Batteries, Chemical, Storage, Supercapacitors, Telecommunication, Wireless
Chemical batteries, in a word, are Toxic. There is nothing environmental about them from the mining, to the leakage, to the disposal. Throughout their life-cycle they have terrible impact on the environment.