High capacity lithium silicon battery with hollow Si microspheres loaded with porous carbon nanotubes as anode

In order to improve the electrochemical performance of lithium ion battery, a porous conductive current collector was fabricated mixing multiwalled carbon nanotubes (MWCNTs) and cellulose fibers through vacuum filtration method. The cellulose fibers were used as the matrix and MWCNTs as the conductive agent. The porous conductive paper of MWCNTs/paper fiber was used as cathode current collector instead of copper foil. The hollow Si microsphere doped with MWCNTs was used as active materials. FESEM was used for characterization. The results show that active substances of hollow Si-MWCNTs are well dispersed in network of MWCNTs conductive paper, which ensures the structural stability and chemical stability at the same time. The results show excellent cyclic stability and higher specific capacity, and also reversible. The capacity of the lithium ion battery reachs 1 300 mAh/g after 30 cycles at a rate of 0.02 C. The capacity still maintain 330 mAh/g at the current density of 3 C. When the current density reduces to 0.25 C, the capacity can be restored to as high as 1 150 mAh/g.