Atomic layer deposition of TiO ₂ on graphene for supercapacitors

A nano-scaled coating of titanium oxide (TiO ₂) on graphene (G) has been achieved via a novel atomic layer deposition (ALD) method. As a potential supercapacitor material, the TiO ₂-G composites exhibited a capacity of 75 Fg and 84 Fg at a scan rate of 10 mVs for composites grown using 50 and 100 ALD cycles, respectively. The nearly identical Nyquist plots of the TiO ₂-G composites compared with those of pure graphene demonstrated that the composites possess excellent conductivity for charge transfer and open structures for ion diffusion. In addition, even with 3-4 times additional mass loading (maximum 3.22 mgcm ²), the composites exhibit no obvious degradation with respect to the electrochemical performance. This ALD approach presents a promising route to synthesize advanced graphene-based nanocomposites for supercapacitor applications.