May 3, 2025

Vastly improved Li-Ion batteries for electric vehicles towards reduced weight, increased range and faster charging

The Li-Ion battery technology has seen a significant advance in the last decade. For example a three-fold increase in energy density along with a 6-fold reduction in price has resulted in a significant uptake of electric vehicles (EVs) in the transportation sector. It is therefore a forgone conclusion that increasing market share of EVs in the transportation sector is strongly dependent on advances in batteries’ energy density. Despite their commercial success, Li-Ion batteries still need to be greatly improved to meet energy and power demands in the various commercial and military sectors. Therefore, improved performance in terms of cycle life, energy density and fast charging capabilities, will have a significant impact on making EVs more ubiquitous on the road, and on mobility in general. An area where improvement is critically needed concerns charge retention for long periods of time and rate capability of the battery – its ability to deliver large capacity when discharged at high C rates. It is now well established that these limitations in the rate capabilities are caused by slow solid-state diffusion of Li ion within the electrode materials. As a result, there is tremendous interest in the development of nanostructured electrodes as an alternative to the polycrystalline microparticulate graphite anode which has been one of the major limiting factors in further improvement of current technology. We have developed a nanostructured anode material that is thus far the best performing anode material with an energy density that is several factors better than that of graphite, which will potentially more than double the energy density of battery packs used in EVs. We intend to develop this material further and implement its use in batteries for EVs (https://www.sbir.gov/awards/127416).

May 1, 2025

Self-healing Supercapacitors

Thanks to their high efficiency and long cycle life, supercapacitors are increasingly being used in consumer electronics, automotive applications, and beyond. However, these capacitors can suffer damage when subjected to elevated temperatures and mechanical stress. A recent review article [1] outlines various strategies to mitigate such internal damage through self-healing mechanisms-both intrinsic and extrinsic-based on chemical and electrochemical processes. These approaches aim to extend the operational life of supercapacitors and the devices that rely on them. Materials employed as self-healing additives include self-healing polymers and gels, conductive polymers, and nanomaterials such as carbon nanotubes, graphene sheets, and transition metal carbides and nitrides. While notable progress has been made toward developing commercially viable self-healing capacitors, challenges persist, particularly in balancing high electrochemical performance with effective self-healing functionality.

[1]. J. M. Yelwa et al, Academia Green Energy, https://doi.org/10.20935/AcadEnergy7555

April 28, 2025

Asymmetric Supercapacitors
 
Supercapacitors are of great benefit for numerous markets particularly automotive, consumer electronics and storage systems for the grid, which require highly reliable energy sources with good power delivery. As a pulse power source, supercapacitors constitute a great supplement to batteries used for energy storage during periods of peak loading.
 
Fabrication of high energy and power density supercapacitors in a wide temperature range is critical for their successful implementation in the automotive and consumer electronics markets. Performance of supercapacitors is dependent on their capacitance and voltage. Using high capacitance materials in conjunction with an asymmetric construct and ionic liquids electrolytes makes it possible to increase both capacitance and voltage. The use of ionic liquids contribute to a wide voltage window and stability at high temperatures .
 
An example of a good asymmetric capacitor consists of metal oxide xerogels and aerogels, intercalated with intrinsically conducting polymers as cathode nanocomposite materials, and an activated carbon anode in an ionic liquid electrolyte. The increased voltage due to the asymmetric construction and the wide voltage window of the ionic liquid electrolyte lead to high performance capacitors with energy densities in the battery range, and power densities comparable to some of the best capacitors.