Few-Layered MoSe2 Nanosheets Confined in N,P-Doped Carbon Polyhedra for Sodium/Potassium-Ion Storage

Few-layered MoSe2 nanosheets are significant for energy storage due to more active edges and improved conductivity. Herein, the cavity confinement effect of structure-efected UiO-66-NH2 is applied to host H3PMo12O40 units, which can be transformed into few-layered MoSe2 nanosheets confined into N,P-doped carbon polyhedrons (MoSe2/N,P-C) for fast Na+/K+-ion storage. Also, this unique architecture can provide sufficient active sites, alleviate the mechanical strain, and offer spacious channels for Na+/K+-ion transfer. Particularly, MoSe2/N,P-C(5:1) possesses superior sodium storage capability (316 mA h g(-1) at 2.0 A g(-1) within 300 cycles), promoted by the accelerated reaction kinetics and capacitive effect. In addition, an ultralong cycling stability with an expected capacity of 177 mA h g(-1) (1.0 A g(-1) after 1000 cycles) and a high rate capability (139.9 mA h g(-1) at 10.0 A g(-1)) can be achieved for the K+-ion storage. Ex situ Raman spectra and X-ray diffraction analysis imply a combined mechanism of a reversible intercalation-conversion process for active MoSe2 and partial reversibility of the N,P-C skeleton. In addition, the assembled MoSe2/N,P-C//Na3V2(PO4)(3)/C full cell also exhibits a capacity of 322.5 mA h g(-1) at 0.5 A g(-1), implying the potential application in practice.

Automated summary

Few-layered MoSe2 nanosheets confined into N,P-doped carbon polyhedrons demonstrate superior sodium storage capability and ultralong cycling stability, with potential application in practice. The unique architecture provides active sites, alleviates mechanical strain, and offers spacious channels for ion transfer. Additionally, the assembled full cell exhibits a high rate capability for K+-ion storage.