New rock-salt anode makes battery charging safer -Lithium - Ion Battery Equipment
Why does it take so long to fully charge the battery? The big reason is that the design of battery devices and their chargers is such that lithium batteries can only be charged at a slow, controlled rate. This is a safety feature that helps prevent fires and even explosions, as tiny, hard dendrites develop inside lithium batteries, which can cause internal short circuits when charged quickly.
To address the need for more practical lithium batteries, researchers from the University of California, San Diego (UCSanDiego) teamed up with scientists at Oak Ridge National Laboratory (ORNL) to conduct neutron scattering experiments on a new material that can Used to make safer and faster rechargeable batteries.
The researchers made samples of lithium vanadium oxide (Li3V2O5), a "disordered rock salt" similar to table salt, but with a degree of randomness in the arrangement of its atoms. The sample is placed in a powerful neutron beam that, when a voltage is applied, observes the activity of ions inside the material. The research results have been recently published in the well-known scientific journal Nature.
"The two most commonly used anode materials for lithium batteries are graphite, which can supply high energy density but can cause fires in some cases, and lithium titanate, which It can be charged quickly and is less likely to cause a fire, but the energy storage capacity is low."
"The disordered rock salt material we developed combines two sought-after properties - it is safer, charges faster, and has a higher energy density," he added.
The material is said to exhibit desirable properties, such as energy storage and discharge speed, in many battery applications such as electric vehicles and other power tools.
In tests, the rock-salt anode material was able to supply more than 40 percent of its energy capacity in just 20 seconds. The fast charging and discharging are possible because the rock salt material can cycle two lithium ions in holes within its crystal structure.
"The neutron diffraction technique used by ORNL allows us to understand the behavior of ions when we apply a voltage to the material," Liu said. Sub-Source (SNS)'s VULCAN instrument provided the high neutron flux and resolution we needed."
VULCAN is designed for neutron studies of deformation, phase transformation, residual stress, texture and microstructure of engineered materials. Loading frames, furnaces, battery cyclers, and other auxiliary equipment for field testing, steady-state or time-resolved measurements are integrated with the instrument.
"VULCAN is the world's premier neutron scattering instrument for studying engineered materials," said KeAn, a neutron scattering scientist at ORNL. "Its open design allows testing of large samples, even functioning machinery, such as a running internal combustion engine, and observe their internal properties. The instrument provides important scientific information for energy storage studies during the synthesis of battery materials and their behavior in working batteries."
The researchers say the rock-salt anode can be cycled more than 10,000 times with negligible capacity fading. This persistence is important for consumer applications. UC San Diego reserves its rights to the data and any intellectual property rights arising from the experiments.
To commercialize their findings, the university then partnered with its researchers to form a company called Tyfast, which plans to first target the electric bus and power tool markets.