Most batteries in portable consumer electronics are lithium-ion batteries. The demand for ever higher battery capacities causes a need for better anode materials for such batteries.

An-Min Cao, Li-Jun Wan, Chinese Academy of Sciences, Beijing, China, and colleagues have developed a synthesis protocol for hollow SnO₂-C microspheres which can improve battery performance when used as an anode material in lithium-ion batteries. The team created a cavity inside the microspheres without using a preexisting template.

They used a urea-formaldehyde polymerization to induce aggregation of the particles in a SnO₂ sol and encapsulate them in the polymer (a so-called polymerization-induced-colloid-aggregation process). Then, a heat treatment was used to create the cavity and carbonize the polymer. During the treatment, SnO₂ crystallizes on the spheres’ surface, and then the crystallization proceeds inward. The material contracts during the process, which leaves the spheres hollow.

The researchers tested the hollow microspheres’ suitability as an anode material for lithium-ion batteries. They found that the material is electrochemically stable and shows good cyclability and rate capability.

• Designed synthesis of SnO₂-C hollow microspheres as an anode material for lithium-ion batteries,
  Lin-Lin Hu, Li-Ping Yang, Dong Zhang, Xian-Sen Tao, Chen Zeng, Li-jun Wan, An-Min Cao,
  Chem. Commun. 2017.
  DOI: 10.1039/c7cc05747d