Porous hollow carbon spheres decorated with molybdenum diselenide nanosheets as anodes for highly reversible lithium and sodium storage.

Porous hollow carbon spheres (PHCS) decorated with MoSe2 nanosheets (MoSe2@ PHCS) are synthesized via a three-step process. Uniform and conformal MoSe2 nanosheets are firmly attached to PHCS according to the characterization of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. Enhanced electrochemical performance of MoSe2@PHCS is investigated in lithium-ion and sodium-ion storage. The MoSe2@PHCS deliver a reversible lithium storage capacity of 681 mA h g(-1) for 100 discharge/charge cycles. In Na-ion batteries, it manifests a reversible sodium capacity of 580 mA h g(-1) after 100 cycles. Three synergic effects can be attributed to the enhanced electrochemical performance of MoSe2@PHCS: (1) both the sheet structure of the MoSe2 and the mechanically robust carbon sphere supporter can accommodate stress from cycling; (2) the porous hollow carbon spheres matrix in the MoSe2@PHCS offers a beneficial conductivity environment; (3) uniform and conformal MoSe2 nanosheets attachment shortens the electronic lithium-ion and sodium-ion pathway during cycling. The MoSe2@PHCS have a great potential as an anode for lithium and sodium batteries.