Re ECF Project: 2014-45

Project Title: Development of high capacity battery materials to improve driving range of electric vehicles

Applicant: Dr. Denis Y.W. YU, City University of Hong Kong

Total Approved Grant: $499,980

Duration: 1/6/2015 to 31/5/2017

Project Status/Remarks: Completed

Electric vehicles are vital to reducing air pollution. There are numerous electric vehicles in the market, but the driving range of 100-150 km is relatively low. The main limitation is the battery material that is used. New materials that can give higher capacity need to be developed. The proposed project aims to increase the capacity of battery materials (cathodes). The scope of the work is two-fold:

  1. to develop low-cost cathode materials that can deliver higher capacity than existing materials; and
  2. to develop inert solid electrolyte as ionic conductive surface coating on materials to suppress material degradation and electrolyte decomposition.

Summary of the Findings/Outcomes:
In this project, a new low-cost layered material with Iithium manganese oxide has been successfully synthesized at low temperature by carbothermal process. The material can be used as cathode material for lithium-ion battery. The material delivers an initial capacity of more than 200 mAh g-1, about 30% higher than the capacity of LiCo02 in commercial batteries. It means that with the same amount of cathode weight, 30% more charges can be stored. It has the potential to be used in advanced batteries, in particular to increase driving distances of electric vehicles. One of the drawbacks of the material is its poor stability with decrease in capacity upon charge and discharge due to structural change of the material, surface reactions between material and electrolyte and dissolution of Manganese from the material. The research team has successfully suppressed degradation of the material by removing impurities from the material, by doping the material with other transition metals, and by surface coating the material with inorganic metal oxide or polymers. With the research team’s efforts, more than 90% of the capacity can be maintained after 50 cycles. A manuscript was published in the Journal of Alloys and Compounds.