The research was led by Dr Xuekun Lu from Queen Mary University of London in collaboration with an international team of researchers from the UK and USA. Their findings are detailed in Nature Communications.
Lithium plating can occur in lithium-ion batteries during fast charging; the lithium ions accumulate on the surface of the battery's negative electrode instead of intercalating into it, forming a layer of metallic lithium that continues growing. This can damage the battery, shorten its lifespan, and cause short circuits that can lead to fire and explosion.
According to Dr Xuekun Lu, lithium plating can be significantly mitigated by optimising the microstructure of the graphite negative electrode. The graphite negative electrode is made up of randomly distributed tiny particles, and fine-tuning the particle and electrode morphology for a homogeneous reaction activity and reduced local lithium saturation is the key to suppress lithium plating and improve the battery's performance.
"Our research has revealed that the lithiation mechanisms of graphite particles vary under distinct conditions, depending on their surface morphology, size, shape and orientation. It largely affects the lithium distribution and the propensity of lithium plating," Dr Lu said in a statement. “Assisted by a pioneering 3D battery model, we can capture when and where lithium plating initiates and how fast it grows. This is a significant breakthrough that could have a major impact on the future of electric vehicles.”
The study is claimed to provide new insights into developing advanced fast charging protocols by improving the understanding of the physical processes of lithium redistribution within graphite particles during fast charging. This knowledge could lead to an efficient charging process while minimising the risk of lithium plating.
In addition to faster charging times, the study also found that refining the microstructure of the graphite electrode can improve the battery's energy density, so electric cars could travel further on a single charge.
The team’s findings could lead also to faster charging, longer lasting, and safer electric cars, which would make them a more attractive option for consumers.