Adding a controlled amount of silicon to the graphite normally used in the anode of a lithium-ion battery may double the energy storage capacity of that battery, researchers at the US Department of Energy's Sandia National Laboratories.
If the advance can be commercialised, it will lead to rechargeable lithium-ion batteries with more power, longer life and smaller size, givng more scope to designers of laptops, notebooks, PDAs and mobile phones.
The anode, or electrically negative part of the battery, has, traditionally, been made of graphite to complement the lithium cathode, or positive part. Although silicon offers more than 10 times the charge capacity of graphite, it suffers rapid capacity loss during the discharging and recharging cycle.
The researchers discovered that by adding small particles of silicon into a graphite matrix, the large battery capacities can be maintained. The new silicon/graphite anode combines large capacity with better capacity retention during cycling than other high-capacity materials.
Designers also have the ability to control the anode's performance by changing the composition and microstructure of the graphite/silicon mix, the researchers claimed.
The graphite/silicon anode can be produced by conventional milling techniques and uses abundant and cheap raw materials.
Sandia is looking for partners to help with commercialising the new technology.