Lab Creates Graphene Composite for Lithium Ion Batteries

Graphene molecular illustration (Lawrence Berkeley National Laboratory)

Researchers with the Lawrence Berkeley National Laboratory in California have developed a graphene and tin nanoscale composite material for high-capacity energy storage in renewable lithium ion batteries, like those used in electric cars. The team at the lab, funded by the Department of Energy, published its findings in a recent issue of the journal Energy and Environmental Science (Paid subscription required).

Graphene is a single-atom-thick layer of carbon formed in a lattice resembling chicken wire. The material has higher performing electronic and mechanical properties that exceed silicon and other traditional semiconductor materials.

Berkeley Lab’s Yuegang Zhang and colleagues layered tin between sheets of graphene to construct a lightweight structure that should bolster lithium ion battery performance. The team assembled alternating layers of graphene and tin to create a nanoscale composite; 1 nanometer = 1 billionth of a meter. This process is repeated to create a composite material, which is then heated to 300 degrees Celsius (572 degrees Fahrenheit) in a hydrogen and argon environment. During this heat treatment, the tin film transforms into a series of pillars, increasing the height of the tin layer.

The change in height between the graphene layers in these nanocomposites increases the volume of tin, which helps improve the performance of electrodes during electrochemical cycling of the battery. In addition, these volume adjustments mean the battery can be charged quickly and repeatedly without degrading, which is crucial for rechargeable batteries in electric vehicles.

Read more: Simple, Safer Process Developed to Synthesize Graphene

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