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Towards the development of fast, stable, health/environment friendly and sustainable Na-ion batteries

Currently Li-ion batteries dominate the market share, powering electronic gadgets and electric vehicles world over, due to their high energy density and design flexibility. However, the scarcity of Li-reserves and rapidly increasing demand for Li-ion batteries for widespread applications strongly defy sustainability. Accordingly, the need for developing less expensive and sustainable alternatives has directed the focus towards the upcoming Na-ion battery system; especially in countries like India, which is third largest producer of sodium.
However, there are certain bottlenecks associated with the Na-ion battery system. One among them is the availability of a safe and electrochemically stable anode material; since graphite, the workhorse anode material in ‘conventional’ Li-ion batteries, does not work for Na-ion batteries. A popular potential anode material is hard carbon, but which possesses issues concerning safety and irreversibility. The other bottleneck is the absence of a cathode material which promises high energy density, exhibits ‘long-term’ electrochemical stability and possesses stability upon exposure to air/water. Against these backdrops, the NCPRE research team working under Prof. Amartya Mukhopadhyay have addressed both the above issues by leading to the development of a ‘bi-phase’ Na-titanate based anode material and compositionally/structurally engineered high Na-containing ‘layered’ Na-TM-oxide (TM => transition metal) based cathode material.

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The ‘bi-phase’ Na-titanate based anode possesses a ‘safe’ operating potential, exhibits very long-term stability upon repeated discharge/charge and allows for extremely fast charging/discharging, so much so, >80% of its Na-storage capacity can be accessed in < 3 minutes. At the cathode front, our newly developed Na-TM-oxide not only exhibits very good long-term cyclic stability, but also inherently possesses excellent stability against degradation in the presence of moisture/water (unlike other variants); thus enabling electrode preparation via the health/environment-friendly and cost-effective aqueous route, which, in itself is a significant development for the Na-ion battery system.

Prof. Amartya
Bachu Sravan