Journal: Advanced Materials
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Sticky spheres of silicon enhance electrodes
Rechargeable batteries could deliver strong power for longer thanks to reinforced silicon spheres.
Silicon is a popular material for electrodes in rechargeable batteries, but it swells and shrinks, which eventually breaks the electrical contact. Protecting silicon inside a carbon shell can overcome this, but producing these spheres is complex and requires toxic chemicals.
A team including researchers from the University of Wollongong built an electrode from spheres of silicon in carbon shells, each with a silica core. The silica provided extra structural support while a gap between the silicon spheres and outer carbon shells accommodated swelling. The researchers then bound the nanospheres together with a mixture of cellulose and citric acid — two cheap and environmentally friendly chemicals. In a sample fuel cell, the electrode provided high electrical charge and retained 85 per cent of its original charge after 1,000 charge-discharge cycles.
These electrodes could improve the performance and safety of the next generation of rechargeable batteries.
- Advanced Materials 29, 1703028 (2017). doi: 10.1002/adma.201703028