Researchers have developed a new anode material for sodium-ion batteries using titanium dioxide nanosheets. These sheets are 10 nm thick and arranged into hollow, double-shelled spheres. Each sheet is coated with a 0.4 nm layer of carbon with a graphene-like structure to enhance conductivity and prevent structural degradation.
In laboratory tests, the material maintained a capacity of 131 mAh/g over 10,000 cycles with a six-minute charge time. When charged in approximately 30 seconds, the capacity remained at 121 mAh/g. For comparison, uncoated nanosheets failed after only 400 cycles.
The protective carbon layer facilitates faster electron transfer and prevents the nanosheets from cracking during rapid charging. It also limits contact with the electrolyte, which slows the formation of a film that typically consumes sodium and degrades battery performance.
A prototype battery using a sodium vanadium phosphate cathode was also tested, sustaining over 170 cycles under high load. The electrodes remained functional even with increased mass loading, a common bottleneck in lab-scale battery development.
Despite these results, the technology is not yet ready for mass production. The material operates at a higher average voltage than traditional hard carbon, which may reduce overall energy density. Further testing in full-scale battery formats is required.
