Deciphering the functionalization routes for SnO 2 anodes

In this report, investigations on pristine vs. hybrid SnO 2 modified by four different routes are reported. The pristine SnO 2 is a potential anode with high theoretical capacity (1494 mAhg −1 ), but the volumetric issues prevails the viability of this material in Li-ion battery systems. For enhancing the stability and anode specific properties, SnO 2 is incorporated with CNT, ZnO, Li, and amorphous/less crystalline phase of its own. Both physical and electrochemical aspects of the SnO 2 experience huge improvement on changing its pristine nature. Structural analysis made by XRD indicates that except SnO 2 /ZnO matrix, all the samples are phase pure falling into the tetragonal symmetry. SnO 2 /ZnO sample possesses mixed tetragonal and hexagonal symmetry. The presence of foreign elements greatly impacts the morphological patterns of the sample as ensured by TEM analysis. Doping helps in bandgap engineering of the pristine material by decreasing the energy gap value and thereby improving the redox properties of pristine. Cyclic voltammetry analysis shows betterment in the electrochemical properties of the SnO 2 material, whereas galvanostatic charge–discharge analysis shows specific capacitances, 158 mAhg −1 , 450 mAhg −1 , ~ 225 mAhg −1 , 425 mAhg −1 , 275 mAhg −1 with respect to SnO 2 , SnO 2 /CNT, SnO 2 /ZnO, SnO 2 /Li, and composite SnO 2 for 1000 cycles with a Coulombic efficiency of ~ 99% except SnO 2 /Li. Overall, the order of anodic performance of the materials is sorted as, SnO 2 /CNT, SnO 2 /Li, SnO 2 /ZnO, composite SnO 2 , and pristine SnO 2 . In summary, the investigations on SnO 2 hybrids have shown promising results in improving their properties, especially in capacitance and life time. Inspired by this, future investigations related to SnO 2 hybrids will likely revolve around optimizing their anodic properties by improving their long-term stability and compatibility with different battery materials.