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.