Based on the stable tunnel structure of C@K2Ti6O13 hybrid compositions for supercapacitor

Controllable synthesis of Na, K-based titanium oxide nanoribbons as functional electrodes for supercapacitors and separation of aqueous ions

By facile controllable preparation, as-synthesized NTO and KTO exhibit remarkable electrochemical behavior for the applications of supercapacitors and capacitive deionization.

K2Ti6O13 Nanoparticle-Loaded Porous rGO Crumples for Supercapacitors

One-dimensional alkali metal titanates containing potassium, sodium, and lithium are of great concern owing to their high ion mobility and high specific surface area. When those titanates are combined with conductive materials such as graphene, carbon nanotube, and carbon nanofiber, they are able to be employed as efficient electrode materials for supercapacitors. Potassium hexa-titanate (K₂Ti₆O₁₃, KTO), in particular, has shown superior electrochemical properties compared to other alkali metal titanates because of their large lattice parameters induced by the large radius of potassium ions. Here, we present porous rGO crumples (PGC) decorated with KTO nanoparticles (NPs) for application to supercapacitors. The KTO NP/PGC composites were synthesized by aerosol spray pyrolysis and post-heat treatment. KTO NPs less than 10 nm in diameter were loaded onto PGCs ranging from 3 to 5 µm. Enhanced porous structure of the composites was obtained by the activation of rGO by adding an excessive amount of KOH to the composites. The KTO NP/PGC composite electrodes fabricated at the GO/KOH/TiO₂ ratio of 1:3:0.25 showed the highest performance (275 F g^-1) in capacitance with different KOH concentrations and cycling stability (83%) after 2000 cycles at a current density of 1 A g^-1.

In situ growth of MnO@Na2Ti6O13 heterojunction nanowires for high performance supercapacitors

One-dimensional tunnel and layer frame crystal structure materials are extremely attractive for energy storage in electrode materials. The energy storage properties of the electrode materials depend on their conductivity. Furthermore, the conductivity of electrode materials can be tailored through combination or doping with other materials, which transforms their properties from semiconductor to semimetallic or metallic and allow them to show unequaled performance for storage devices. In this work, heterostructures of manganese oxide (MnO) and modified sodium titanate (Na₂Ti₆O₁₃) (MnO@Na₂Ti₆O₁₃) nanowires are attained by the in situ thermal decomposition method. The heterojunction between MnO and Na₂Ti₆O₁₃ allows the semiconductor properties of pure Na₂Ti₆O₁₃ to show remarkable metallic behavior for improving the electrochemical performance. The capacitance of MnO@Na₂Ti₆O₁₃ heterojunction nanowires can reach 272.3 F g^-1, a power intensity of 250 W kg^-1 at the energy density of 37.83 Wh kg^-1 and retain 5000 W kg^-1 at 6.67 Wh kg^-1 as well. The energy storage mechanism of the MnO@Na₂Ti₆O₁₃ heterostructure is studied by density functional theory. All of the results show that the MnO@Na₂Ti₆O₁₃ heterostructure material has the potential to be an excellent supercapacitor material in the future.