Rutile-TiO2 decorated Li4Ti5O12 nanosheet arrays with 3D interconnected architecture as anodes for high performance hybrid supercapacitors†
Abstract
Herein, we report on rutile TiO2 decorated hierarchical Li4Ti5O12 nanosheet arrays for lithium ion hybrid supercapacitor application for the first time. It is noted that the self-supported arrays manifest impressive rate capability and cycling stability, showing a reversible specific capacity of 142.9 mA h g−1, and retaining 92.3% of their initial capacity over 3000 cycles at a rate of 30C. The lithium ion hybrid supercapacitor, constructed with Li4Ti5O12 nanosheet arrays and nitrogen doped carbon nanotubes (N-CNTs), exhibits an ultrahigh energy density of 74.85 W h kg−1 at a power density of 300 W kg−1. The hierarchical 3D interconnected nanostructure of the self-supported Li4Ti5O12–rutile TiO2 nanosheet arrays, as well as the efficient lithium diffusion along the [011] direction for Li4Ti5O12 and [001] for rutile TiO2, play an important role in the outstanding energy storage performance.