Physics

Dr. V. Aravindan
Nanyang Technological University, Singapore

Increasing solicitude about global warming and depletion of fossil fuels, the energy consumption from renewable clean sources is one of the efficient alternate approaches rather than utilising conventional ones for sustainable earth. Reliable and sustainable energy storage systems are desperately required to fulfil the necessary energy demands. Currently in the electrical market, the available and extensively studied Li-ion batteries (LIB) are used and remain popular by considering its advantages like shape versatility, flexibility, high energy and long cycle life. However, concerns over the inherent limitations, poor power capability, cost and recycling pollutions are certainly hindered their potential application to large-scale electrical-energy storage, but R&D is still underway to overcome those limitations.

In LIB, intercalation concept (Rocking chair) has been predominantly used, since its introduction in to commercial market in 1991 by Sony. Unfortunately, the poor performance of graphitic anode at high current operation and possible Li-platting issue hinders to realize the high energy density. This certainly dilutes the possibility of using them in high end applications like grid storage and zero emission transportation (EV and HEV). To power such applications, high energy Li-ion power packs are desperately required. Therefore, adopting conventional intercalation mechanism is not possible to realize the goal. Conversion and alloy type materials are another class of fascinating anodes with high capacity and high power capability than conventional graphitic anodes. However, such anodes are facing the serious volume variation, stability and irreversible capacity loss issues. The said issues has to be addressed before being employed in commercial cells. This talks deals the possibility of using both conversion (Fe based oxides) and alloy (SnO₂) type materials in practical assemblies and its challenges. Furthermore, the same concept could be easily translated in to another hybrid charge storage device, Li-ion capacitor which is anticipated to replace the conventional electric double layer supercapacitors in near future.