Most microelectronic devices use lithium-ion batteries as their main power source. This is due to their high power density and long life. However, current trends in microelectronic evolution demand higher energy output and therefore there is need to develop new electrode materials with improved cycling stability, high power density and higher safety. For a long time, graphite has been the main anode material despite the fact that it poses safety issues related to lithium dendrites formation. Dendrite formation is attributed to the relatively low lithium ion intercalation potential, overcharge and high current. Recently, titanium based oxides have drawn much attention. Specifically, Titanium-Niobium-Oxide (TNO) has received a higher concern due to its high theoretical capacity and a higher discharge platform. Unfortunately, fabricating TNO is quite challenging as it requires high temperatures for processing and a long reaction time. More so, the particle size and morphology, which display a significant influence on the electrochemical performance, cannot be effectively controlled.
A team of researchers led by Professor Bo Jin from the Key Laboratory of Automobile Materials, at Jilin University in China developed a facile preparation technique for fabricating TNO materials with a meticulous morphology that would ensure improved electrochemical performance. They aimed at fabricating the TNO microspheres by combining a solvothermal method with a subsequent heat-treatment. Their work is now published in International Journal of Hydrogen Energy.
The researchers commenced the proposed investigation by preparing TNO microspheres. They then characterized the structural and morphological properties of the prepared samples by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption. Eventually, they evaluated the electrochemical performance by performing cyclic voltammograms and galvanostatic discharge/charge tests.
From the electrochemical tests undertaken, the authors of this paper were able to demonstrate that the as-prepared TNO microspheres exhibited high yet stable electrochemical properties. To be precise, they noted that TNO microspheres exhibited a discharge capacity of 185 mAh g-1 after 200 cycles at 10 C. The team therefore argued that the good electrochemical properties of TNO microspheres were ascribed to its convenient structure with porosity and small particle size, which favors the infiltration of the electrolyte, accelerates Li-ion diffusion, and improves the cycling lifetime by an efficient accommodation of the volume change upon charging/discharging.
In their study, Bo Jin and colleagues have presented a new facile technique for fabricating TNO materials of improved electrochemical performance. From the electrochemical characterization undertaken, it has been demonstrated that the as-prepared TNO microspheres exhibit a good electrochemical performance with an excellent discharge capacity and an outstanding capacity retention. This is a clear indication that the proposed TNO microspheres are prospective high power anode materials application which may react with lithium at voltages above 1.0 V vs. Li+/Li.
Ti2Nb10O29 – Titanium-Niobium-Oxide (TNO)
Guangyin Liu, Bo Jin*, Keyan Bao, Ying Liu, Haiquan Xie, Min Hu, Ruixue Zhang, Qing Jiang. Facile fabrication of porous Ti2Nb10O29 microspheres for high-rate lithium storage applications. International Journal of Hydrogen Energy volume 42 (2017) pages 22965-22972.
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