Rechargeable lithium-ion batteries have become the battery of choice for everything from cell phones to electric cars, but there is still much room for improvement. Scientists at Argonne National Laboratory are leading efforts to revolutionize battery technology with the design and development of new battery materials for electrolytes, electrodes, and interfaces that will increase the specific energy of advanced batteries, while simultaneously providing enhanced stability at a lower cost. To help improve the stability and safety of lithium-ion batteries, Argonne researchers have developed a new class of intermetallic materials that can be used for the battery’s negative electrode.
Conventional lithium-ion battery configurations often contain graphite electrodes, which operate at a potential very close to that of metallic lithium and are extremely reactive. This composition can cause lithium-ion batteries to overheat, particularly if the battery is in a charged state or if it is overcharged without protective electronic circuitry. Argonne scientists have developed a new intermetallic structure type that can be effectively used as a negative electrode (anode) for non-aqueous lithium electrochemical cells and batteries.
The composition of these new electrodes contains the basic structural unit of a MM'3 intermetallic compound with a LaSn3-type structure, in which the M and M' atoms are comprised of one or more metals. The Argonne innovation reveals a new class of negative electrode materials for lithium-ion batteries that operate either by lithium insertion or by metal displacement reactions or a combination of both.
In addition to improving on the safety of current graphite electrodes, these new intermetallic electrodes offer greater structural stability to lithium insertion and extraction reactions. The Argonne-developed electrodes also provide a superior charge capacity. The LaSn3-type structure resulted in specific and gravimetric capacities of 650 mAh/g and 4920 mAh/mL, respectively (based on a density of 7.57 g/mL). This compares to graphite’s specific capacity of 372 mAh/g and gravimetric capacity of 818 mAh/mL (based on a density of 2.2 g/mL).
Applications and Industries
- Transportation applications, such as electric and hybrid-electric vehicles
- Portable electronic devices, such as cell phones and laptop computers
- Medical devices
- Space, aeronautical, and defense-related devices
- Significant improvement in energy density
- Improves safety
- Increases reliability
- Greater structural stability
- Superior charge capacity