Hybrid MnO-SiOx@C microspheres with a hierarchical mesoporous structure for advanced lithium-ion battery anodes

A novel porous structure MnO-SiOx @C composite has been designed and prepared as an anode material for lithium-ion batteries through scalable spray pyrolysis and a subsequent annealing process. XRD, SEM, TEM, Raman, and BET measurements indicate that the MnO-SiOx @C composite displays a spherical mesoporous structure with SiOx particles, embedded in the porous MnO structure combined with carbon coated on the surfaces. The enhanced electrochemical performance can be attributed to the mutual segregation of the heterogeneous oxides of MnO and SiOx during delithiation and the buffer composition region at the origin of uniform carbon layers and abundant nanopores. In addition, the new phase Mn2SiO4, which is formed in the MnO-SiOx @C composite after 800 ºC, can act as the joint between MnO and SiOx to restrain the strain force originating from the volume change during the charge and discharge process. As a result, the obtained MnO-SiOx @C composite exhibits significantly enhanced electrochemical performance in terms of high Coulombic efficiency, excellent rate capability and good cyclability.