Researchers at UC San Diego have developed a new anode material that enables lithium-ion batteries to be safely recharged within minutes for thousands of cycles.

Disordered rock salt Li3V2O5 can be used as a fast-charging anode that can reversibly cycle two lithium ions at an average voltage of about 0.6 volts versus a Li/Li reference electrode.

The increased potential compared to graphite reduces the likelihood of lithium metal plating if proper charging controls are used, alleviating a major safety concern (short-circuiting related to Li dendrite growth).

In addition, a lithium-ion battery with a disordered rock salt Li3V2O5 anode yields a cell voltage much higher than does a battery using a commercial fast-charging lithium titanate anode or other intercalation anode candidates (Li3VO4 and LiV0.5Ti0.5S2).

The disordered rock salt Li3V2O5can perform more than 1,000 charge–discharge cycles with negligible capacity decay and exhibits exceptional rate capability, delivering more than 40% of its capacity in 20 seconds.

“We attribute the low voltage and high rate capability of disordered rock salt Li3V2O5 to a redistributive lithium intercalation mechanism with low energy barriers revealed via ab initio calculations. This low-potential, high-rate intercalation reaction can be used to identify other metal oxide anodes for fast-charging, long-life lithium-ion batteries,” say the researchers.

Currently, two materials are used as anodes in most commercially available lithium-ion batteries that power items like cell phones, laptops and electric vehicles.

The most common, a graphite anode, is energy dense; however, recharging a graphite anode too quickly can result in fire and explosions due to a process called lithium metal plating.

A safer alternative, the lithium titanate anode, can be recharged rapidly but results in a significant decrease in energy density, which means the battery needs to be recharged more frequently.

This new disordered rocksalt anode sits in an important middle ground: it is safer to use than graphite, yet offers a battery with at least 71% more energy than lithium titanate.

“The capacity and energy will be a little bit lower than graphite, but it’s faster, safer and has a longer life,” say the researchers, “it has a much lower voltage and therefore much improved energy density over current commercialized fast charging lithium-titanate anodes. So with this material we can make fast-charging, safe batteries with a long life, without sacrificing too much energy density.“