Ceramic-graphene composite shows promise as battery electrode

Replacing the graphite anode commonly used in lithium-ion batteries with ones made of silicon or graphene, which have high lithium uptake capacities, could substantially boost the batteries’ charge capacity, in principle. In practice, however, silicon electrodes swell and shrink with each charging cycle, causing them to crack and fail quickly. Graphene electrodes also quickly lose their capacity to store and release lithium ions.

By combining the two candidate electrode materials, Gurpreet Singh and coworkers at Kansas State University may have hit upon a solution (Nat. Commun. 2016, DOI: 10.1038/ncomms10998).

Starting with a siloxane precursor, the team used a simple heat treatment to form micrometer-sized particles of silicon oxycarbide (SiOC), a glass-ceramic with an open polymer-network-like structure. They then used a standard method to prepare a form of graphene known as reduced graphene oxide (rGO) and finally formed free-standing sheets of an SiOC-rGO composite “paper” via vacuum filtration.

Battery tests show that the low-cost, lightweight paper electrode exhibits a high charge capacity and stands up to repeated cycling. The electrode showed nearly no loss of charge capacity and no sign of mechanical failure even after 1,020 charging cycles, the team reports.