Electrode Innovation Could Triple Laptop Battery Capacity

Researchers at MIT and China’s technology-focused Tsinghua University have developed aluminium-based nanoparticles that could triple the capacity of lithium-ion batteries – the most common type of rechargeable battery, and one commonly used in consumer electronics such as laptop computers.

The discovery, published in the journal Nature Communications, addresses a key factor in degrading the performance of lithium-ion batteries, the fact that their electrodes expand and shrink during each charging cycle, a process that consumes lithium.

The researchers said they have developed an electrode made of nanoparticles with a solid shell and a “yolk” inside that’s isolated in such a way that it can expand and contract without affecting the shell. The technique can greatly improve cycle life, as well as boosting capacity and power.

The electrode’s nanoparticles contain an aluminium yolk and a titanium dioxide shell, resulting in a component whose “skin”, or solid-electrolyte interphase (SEI) layer, is more stable, meaning it doesn’t consume lithium in the way that current batteries do, the researchers said.

“We made a titanium oxide shell that separates the aluminium from the liquid electrolyte” between the battery’s two electrodes, MIT professor Ju Li said in a statement.

‘Chance discovery’

Li, who worked with three others from MIT and three researchers from Tsinghua, said the method was a “chance discovery”.

In laboratory tests, the electrode gave more than three times the capacity of stadard batteries using graphite anodes at a normal charging rate, according to Li. The lab tests found that the battery retained a high charge capacity after hundreds of recharging cycles, he said.

Aluminium is a low-cost material and the team’s method could be easily scaled for industrial-level manufacturing, Li said. The team said it has successfully tested fuel cells using an aluminium-titania (ATO) anode, or negative electrode, with a lithium iron phosphate cathode, or positive electrode.

For high-power, high-density batteries, ANO is “probably the best anode material available”, Li said.

MIT’s Junjie Niu, Kangpyo So, and Chao Wang and Tsinghua’s Sa Li, Yu Cheng Zhao, and Chang An Wang collaborated on the research.

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