Preparation and characteristics of MWNT/SnO₂ nanocomposites anode by colloidal heterocoagulation for Li-ion battery

Through the electrostatic interaction between the poly-diallydimethylammonium chloride (PDDA) modified Multi-walled carbon nanotube (MWNT) and SnO₂ suspension in 1mM NaNO₃ solution, MWNT-SnO₂ nanocomposites (MSC) for anode electrodes of a Li-ion battery were successfully fabricated by colloidal heterocoagulation method. TEM observation showed that most of the SnO₂ nanoparticles were uniformly deposited on the outside surface of the MWNT. Galvanostatic charge/discharge cycling tests showed that MSC anodes exhibited higher specific capacities than bare MWNT and better cyclability than unsupported nano-SnO₂ anodes. Also, after 20 cycles, the MSC anode fabricated by heterocoagulation method showed more stable cycle properties than the simply mixed MSC anode. These improved electrochemical properties are attributed to the MWNT, which adsorbs the mechanical stress induced from volume change and increasing electrical conductivity of the MSC anode, and suppresses the aggregation between the SnO₂ nanopartides.