A fractal-like electrode based on double-wall nanotubes of anatase exhibiting improved electrochemical behaviour in both lithium and sodium batteries. | LitMetric
An anatase nanotube array has been prepared with a special morphology: two concentric walls and a very small central cavity. The method used here to achieve the double-wall structure is a single-step anodization process under a voltage ramp. Thanks to this nanostructure, which is equivalent to a fractal electrode, the electrochemical behaviour is improved, and the specific capacity is higher in both lithium and sodium cells due to pseudocapacitance. The double-wall structure of the nanotube enhances the surface of TiO2 being in contact with the electrolyte solution, thus allowing an easy penetration of the alkali ions into the electrode active material. The occurrence of sodium titanate in the electrode material after electrochemical reaction with sodium is studied by using EPR, HRTEM and NMR experiments.
Aqueous Zn-S batteries provide competitive energy density for large-scale energy storage systems. However, the cathode active material exhibits poor electrical conductivity especially at the discharged state of ZnS. Its morphology generated in cells thus directly determines the cathode electrochemical activity.
Shenzhen institute of advanced technology Chinese Academy of Sciences, Functional Thin Films Research Centre, 1068 Xueyuan Avenue, Shenzhen University Town, 518000, SHENZHEN, CHINA.
Organics electrode materials offer multi-electron reactivity, flexible structures, and redox reversibility, but encounter poor conductivity and durability in electrolytes. To overcome above barriers, we propose a dual elongation strategy of π-conjugated motifs with active sites, involving extended carbazole and electropolymerized crosslinked polymer, which enhances electronic conductivity by the electronic delocalization of electron-withdrawing conjugated groups, boosts theoretical capacity by increasing redox-active site density, and endows robust electrochemical stability attributed to crosslinked organic structures. As a proof-of-concept, 5,11-dihydridoindolo[3,2-b]carbazole (DHIC) is selected as the model cathode material for a dual-ion battery, with elongated carbazole groups functioning both as redox-active centers and polymerization anchors.
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