Microwave‐assisted synthesis and electrochemical characterization of TiNb₂O₇microspheres as anode materials for lithium‐ion batteries

Abstract

TiNb 2 O 7 microspheres are prepared via a microwave-assisted solvothermal method. The microwave irradiation lowers the compound formation temperature to 600 • C, and highly crystalline TiNb 2 O 7 powders are obtained upon calcination at 800 • C. Morphological analysis of the sample shows uniformly distributed microspheres with a particle size of around 1 μm. The Li + -ion diffusion coefficient calculated from the electrochemical impedance result is around 1.21 × 10 −13 cm 2 s −1 , which is 1.5 times higher than the sample obtained from the conventional solvothermal method. The TiNb 2 O 7 sample derived from microwave yields a high discharge capacity of 299 mA h g −1 at 0.1 C, whereas the sample synthesized via the conventional solvothermal process yields only 278 mA h g −1 at 0.1 C. Excellent rate capabilities such as 220 mA h g −1 at 5 C and 180 mA h g −1 at 10 C are also observed for the microwave-assisted solvothermal sample. Moreover, the sample exhibits a large capacity retention of 95.5% after 100 discharge-charge cycles at 5 C. These results reveal the appropriateness of the microwave-assisted solvothermal process to prepare TiNb 2 O 7 powders with superior properties for battery applications.

Leveraging novel microwave techniques for tailoring the microstructure of energy storage materials

“…Under high-temperature conditions, the energy of microwave radiation can significantly affect the internal surface diffusion and aggregation behavior of materials, thereby determining the formation of specific size structures, the generation of nanoparticles, and their properties and exhibiting excellent electrochemical performance. During the microwave-assisted synthesis process, multidimensional nanostructures, such as 0D (Nanodot, Nanosphere, Nanoparticle) [67,68] , 1D (Nanowire, Nanotube, Nanorod, Nanobelt) [69,70] , 2D (Nanosheet, Nanodisk, Nanoflake) [59] , and 3D (Nanoarray, Nanoframe, Hierarchical structure) [71][72][73] , can be produced by controlling factors such as microwave power, exposure time, reaction medium, and precursor concentration. Table 1 [33,45,62, summarizes the energy storage electrode materials prepared/modified under various microwave parameters and reaction conditions.…”