Interface and electronic structure dual-engineering on MoSe2 with multi-ion/electron transportation channels for boosted sodium-ion half/full batteries

It is of great significance to design and prepare high performance anode materials for the development of sodium ion batteries (SIBs). In this work, the innovative approach of interface and electronic structure dual-engineering is applied on MoSe2 to fabricate novel C/N co-doped bilayer hollow structured MoSe2 nanosheets (BH-MoSe2@CNBs). With the comparison of traditional MoSe2/C composite, the sandwich structured MoSe2 with double carbon coating can bring multi-ion/electron transportation channels, favoring the Na+ storage and charge transfer kinetics. Specifically, the inner carbon shell as a supporting skeleton not only restrains the agglomeration of lamellar MoSe2, but also buffers the stress of sodium ions (de)insertion. The outer carbon layer plays a crucial role in adsorbing the polyselenide intermediates, maintaining the stability and reversible capacity of the middle MoSe2 electrode. As anode for SIBs, BH-MoSe2@CNBs exhibit 347 mAh g−1 at 10 A g−1 after 1300 cycles, which is comparable with the previously reported MoSe2-based electrode in SIBs. Additionally, the BH-MoSe2@CNBs//Na3V2(PO4)2O2F full cell can reach an energy density of 107.4 Wh kg−1 at a power density of 3832 W kg−1, indicating the potential practical application. The theoretical calculation is also conducted to confirm the superior Na+ adsorption of BH-MoSe2@CNBs. The interface and electronic structure dual-engineering on MoSe2 can provide innovative points for the exploitation of efficient anode materials for SIBs.