Suppressing lithium plating in batteries for fast-charging EVs

A study led by Dr Xuekun Lu from Queen Mary University of London has found a way to prevent lithium plating in electric vehicle batteries, which could lead to faster charging times. The research findings were published in the journal Nature Communications.

Lithium plating can occur in lithium-ion batteries during fast charging. It occurs when lithium ions build up 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.

Lu said that lithium plating can be 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 homogenous reaction activity and reduced local lithium saturation is key to suppressing lithium plating and improving the battery’s performance.

The research found 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. “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,” Lu said.

The study provides insights into developing advanced fast-charging protocols by improving the understanding of the physical processes of lithium redistribution within the graphite particles during fast charging. This could lead to an efficient charging process while minimising the risk of lithium plating. The study also found that refining the microstructure of the graphite electrode can improve the battery’s energy density. This means that electric cars could travel further on a single charge. The research findings could lead to faster-charging, longer-lasting and safer electric cars.

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