Freestanding Sodium-Ion Batteries Electrode Using Graphene Foam Coaxially Integrated with TiO₂Nanosheets

Abstract

Sodium-ion batteries (SIBs) have attracted great interests for use as the large-scale rechargeable batteries, in which electrode materials are the most crucial components. Here, an ingenious programming of freestanding electrode material is reported for SIBs, which consists of titanium dioxide nanosheets aligned vertically on graphene foams (GF) framework inside and outside forming coaxial frame structure (GF-CF). This frame architecture not only ensures sufficient contact area between active materials and electrolyte but also is beneficial to fast electron transportation. Moreover, the titanium dioxide nanosheets in situ grew on GF, which can inhibit the aggregation of nanosheets and improve the electrochemical kinetics. As freestanding anode material for SIBs, GF-CF exhibits high capacity retention (88.0%) at 50 mA g−1 after 100 cycles and improved rate performance. We also find that ∼45.1% of the total sodium-ion storage comes from capacitive contribution, which could be further improved by diminishing the size of TiO2 nanosheets. The approach of building the desirable coaxial frame structure can be extendedly applied to the architectural construction of electrode materials for other energy devices.

Super Kinetically Pseudocapacitive MnCo2S4 Nanourchins toward High‐Rate and Highly Stable Sodium‐Ion Storage

“…Partial conversion/intercalation reaction are shown at CV peaks of 0.8 and 0.58 V, and that 0.30 V is attributed to the full conversion reaction. These findings are also very similar and able to explain the redox reaction of similarly, recent works 70–72. To examine the capacitive contribution of each redox peak (1−6), the peak values were fitted to evaluate the regression data according to the following equation23,73 where i is the current density.…”

Multiscale Graphene‐Based Materials for Applications in Sodium Ion Batteries

“…The unique 3D porous structure of the graphene network with a large specific surface area allowed more efficient penetration of electrolyte into the MoS 2 nanosheets and shortened ion diffusion time. Wu et al synthesized a similar hybrid structure by in situ growth of TiO 2 nanosheets aligned vertically on a 3D macroporous CVD graphene foam framework both inside and outside (Figure d) . The 45.1% of the total charge storage derived from capacitive effects according to cyclic voltammetry analysis and the further improved capacity of graphene foam/TiO 2 electrode could be obtained by reducing the size of TiO 2 .…”

“…Copyright 2016, Elsevier. d) Reproduced with permission . Copyright 2017, The Electrochemical Society.…”

Self-organized and self-assembled TiO2 nanosheets and nanobowls on TiO2 nanocavities by electrochemical anodization and their properties

“…Nanosheets are nanostructured materials that have a shape of sheet whose thickness is lesser than 100 nm and their length is by the order of a few micrometers [2,3]. Commonly, nanosheets are synthesized either by exfoliation or hydrothermal and solvothermal processes [1][2][3][4][5][6][7] and they have been applied to Li-ion batteries and supercapacitors for improving the charge and discharge time, and in solar cells [1][2][3][4][5][6][7][8]. In 2019, Zhao et al investigated GeSe nanosheets, and demonstrated that these can be used in surface plasmon resonance sensor by depositing it by spin coating, improving the sensitivity of the sensor in the detection of heavy metals and chemical molecular identification [9].…”

“…In 2019, Zhao et al investigated GeSe nanosheets, and demonstrated that these can be used in surface plasmon resonance sensor by depositing it by spin coating, improving the sensitivity of the sensor in the detection of heavy metals and chemical molecular identification [9]. However, all these fabrication processes are highly expensive and do not allow a precise control of the periodicity of the nanostructures [3][4][5][6][7][8][9].…”