Si-decorated CNT network as negative electrode for lithium-ion battery.

We have developed a method which is adaptable and straightforward for the production of a negative electrode material based on Si/carbon nanotube (Si/CNTs) composite for Li-ion batteries. Comparatively inexpensive silica and magnesium powder were used in typical hydrothermal method along with carbon nanotubes for the production of silicon nanoparticles. The X-ray diffraction profile provides conclusive evidence that Si nanocrystals do, in fact, exist. FE-SEM images demonstrated the consistency of coated silicon nanoparticles on CNT wall in the manufactured negative electrode. This one-of-a-kind architecture of Si/CNTs nano-networks not only increases the electrical conductivity of the composite but also allows to accommodate the stress associated with the significant volume change that occurs during the insertion and removal (doping and de-doping as well) of Li-ions. The electrode that is manufactured out of Si/CNTs nano-networks has the ability to offer a very high discharge and charge capacity of 2503 and 1823 mAh g⁻¹, respectively, in the first cycle at 0.1 A g⁻¹. The reversible charge capacity has been found to be 732 mAh g⁻¹ at 0.1 A g⁻¹ while after the 100th cycle, the columbic efficiency increases from initial value of 72 to 95%, and the reversible capacity was found to retain 44%. The presence of multiwall CNT network helps in limiting the enhancement of charge transfer resistance due to pulverization of Si nanoparticle in the composite. [ABSTRACT FROM AUTHOR]