Quantum dot heterostructure with directional charge transfer channels for high sodium storage

Transition metal carbides (TMCs) are viewed as promising anode materials for sodium ion batteries due to high conductivity and chemical stability. However, the sluggish kinetics of Na + and large volume expansion has significantly hindered their practical applications. Herein, we report a universal strategy of loading high work-function metal quantum dots (QDs) to provide a directional charge transfer path by constructing the interfacial Mott-Schottky heterojunction, which broadens space-charge regions and increases regional charge densities. As a proof of concept, 1D hollow tubular nanostructure embedded with Cu QDs and Mo 2 C/MoO 2 nanoparticles was ingeniously synthesized through an in-situ polymerization method with dual chelating agents. Benefiting from both QDs with maximized metal utilization and Mott-Schottky heterostructure with charge transfer acceleration, the electrode displays an unprecedented capacity and rate performance for Mo 2 C-based materials along with ultra-long cycling stability. This work provides an untraditional strategy to enhance sodium storage capability of TMCs, which is significant for development of advanced energy storage devices.