CdSe/ZnS QD@CNT nanocomposite photocathode for improvement on charge overpotential in photoelectrochemical Li-O₂ batteries

Li-ion batteries play a significant role in portable electronic devices in the running world. However, the limited energy density still needs to be improved for the growing future. Hence, we developed a photocathode nanocomposite material composed of Cadmium Selenide/Zinc Sulfide Quantum Dots with Carbon nanotube (CdSe/ZnS QD@CNT) for an efficient and tunable performance of the photoelectrochemical Li–O₂ battery system to overcome the key issue of overpotential. The QD and CNT networks can provide efficient transportation paths of the electron–hole pairs and the O₂ gas and lithium ions, respectively. The charging voltage of the photoelectrode is 2.65–4.0 V; therefore, decreased overpotential was due to efficient oxidation of Li₂O₂ by photoexcited electron–hole pairs by using QDs, resulting in a long-term operational stability over 100 cycles. On the basis of the advantages, the QDs exhibit efficient potential in Li–O₂ batteries.