Enhanced Charge Storage Mechanism and Long-Term Cycling Stability in Diamondized Titania Nanocomposite Supercapacitors Operating in Aqueous Electrolytes

Abstract

The long cycle life stability and high energy density are limiting broader feasible applications of supercapacitors (SCs). The novel diamondized titania nanocomposite SCs deliver high power and energy densities along with high capacitance retention rates. SC electrodes were fabricated utilizing a combination of Ti anodization followed by chemical vapor deposition resulting in the simultaneous growth of the complex boron-doped diamond (BDD)/TiC interface. The first-principles simulations along with extended molecular investigations conducted by bright-field transmission electron microscopy and high resolution-scanning electron microscopy revealed that capacitive phenomena are delivered by nanoporous, multifaceted, and substoichiometric TiC, forming clusters at the lateral surfaces of titania nanotubes. Next, TiC mechanical stability and effective charge transfer electrode–electrolyte are efficiently provided by the highly conductive, although discontinuous BDD overlayer. The assembled two-electrode SC devices exhibited capacitances of 15 mF cm–2, which were stable at 0.1 V s–1 scan rate in various neutral aqueous electrolytes. The composite TiO2 nanotube arrays-BDD SCs showed outstanding long-term cycling stability with a capacitance retention of 93% after 100,000 chronopotentiometry cycles verified by postaging cyclic voltammetry tests. In parallel, the energy and power density calculated at a current density of 3 A g–1 achieved levels as high as 14.74 W h kg–1 and 24.68 kW kg–1, revealing the superior performance of the assembled devices compared to recently reported SCs.

Controlled nanostructure of a graphene nanosheet‐TiO 2 composite fabricated via mediation of organic ligands for high‐performance Li storage applications

“…Figure 3 shows the XPS profiles (Ti 2p, O 1s, and C 1s) of the L‐GNS‐TiO 2 composite, with the characteristic peaks of Ti 2p (459.4 eV), O 1s (531 eV), and C 1s (284 eV) in the spectra demonstrating the surface chemical and electronic states of the composites 4,6,38‐48 . The overall spectra of the L‐GNS‐TiO 2 composite in Figure 3A contain peaks representing only Ti, C, and O 4,6,38‐48 .…”

“…Figure 3 shows the XPS profiles (Ti 2p, O 1s, and C 1s) of the L‐GNS‐TiO 2 composite, with the characteristic peaks of Ti 2p (459.4 eV), O 1s (531 eV), and C 1s (284 eV) in the spectra demonstrating the surface chemical and electronic states of the composites 4,6,38‐48 . The overall spectra of the L‐GNS‐TiO 2 composite in Figure 3A contain peaks representing only Ti, C, and O 4,6,38‐48 . Figure 3B shows the Ti 2p spectra of L‐GNS‐TiO 2 compared to those of the other composite samples, wherein the binding energies of Ti 2p 3/2 (459.4 eV) and Ti 2p 1/2 (465.1 eV) correspond to the Ti 4+ oxidation state of TiO 2.…”

“…Figure 3B shows the Ti 2p spectra of L‐GNS‐TiO 2 compared to those of the other composite samples, wherein the binding energies of Ti 2p 3/2 (459.4 eV) and Ti 2p 1/2 (465.1 eV) correspond to the Ti 4+ oxidation state of TiO 2. 4,6,38,42 A single chemical state of titanium (Ti 2p: Ti 2p 3/2 and Ti 2p 3/2 ) suggests the formation of anatase TiO 2 without carbonaceous TiC 42,43 . Figure 3C shows the O 1s spectra with a primary peak at 530.6 eV and humps at 534 eV.…”

“…Figure 3C shows the O 1s spectra with a primary peak at 530.6 eV and humps at 534 eV. The O 1s signal obtained after deconvolution can be split into three peaks corresponding to TiOTi (Ti 4+ O) bonds (529.9 eV), TiOH or TiOC groups (531.3 eV), and the oxygen‐bound CO species (532.9 eV), respectively; the other oxidation states (Ti 2+ and Ti 3+ ) are not visible 42‐45 . Figure 3D shows the C 1s spectra of the composites, where the C 1s peaks at 284.6 and 289.1 eV indicate the formation of the CC bond and CO (carboxyl group) from carbonaceous materials (carbonized organic ligands and GNS), respectively 46‐48 .…”

An Aqueous Exfoliation of WO3 as a Route for Counterions Fabrication—Improved Photocatalytic and Capacitive Properties of Polyaniline/WO3Composite

“…It makes them interesting for many possible applications [ 1 , 2 , 3 , 4 , 5 ]. As a result of the synergetic effects, enhancing of electrical, electrochemical, photocatalytic or mechanical properties can be observed, and therefore their utilization in various fields like supercapacitors, sensors, photocatalysis and rechargeable batteries is achievable [ 6 , 7 , 8 , 9 , 10 , 11 ]. In the case of such hybrids used as electrode materials, conductive polymers-based systems deserve close attention.…”