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Earlier in 2020, Shiv Nadar University, along with the Indian Institute of Technology (IIT), developed a technology for the production of environment-friendly Lithium-Sulfur (Li-S) batteries.

Auto Futures caught up with Dr. Bimlesh Lochab, Associate Professor at Shiv Nadar University to find out more.

“We have been working on the new S-based cathode structure and its use in Li and Na Sulphur batteries for more than five years now. Our approach has been to incorporate elemental sulphur into an organic carbon network with very specific functionalities and making the electrode more stable and less polysulfide dissolution. The mechanism of such cathode regarding how it works is complex and now, we are studying such mechanism in a more detailed manner.

“Our work also got published in well-reputed journals like ACS Energy letters, Energy Storage Materials, Nature Scientific Reports, etc. where we have utilize different carbon network functionality to get the desired output such as fire-retardant properties as one of kind. During this journey, we recognized that the concept of making such excellent cathode and combine them to a workable battery cell are important in terms of technology development for future programs,” says Lochab.

“Shiv Nadar University’s works involves the usage of sustainable strategies to form the greener cathode -based copolymers and nanomaterials. The Li-S battery technology leverages principles of Green Chemistry, incorporating usage of by-products from the petroleum industry (Sulfur), agro-waste elements and copolymers such as cardanol (a by-product of cashew nut processing) and eugenol (clove oil) as cathodic materials. Our partner in the research, IIT Bombay, assisted with their utility in energy storage devices. We are together working as a strong team to develop high performance sustainable sulphur batteries in future.”

To develop a prototype based on her research, Lochab and her team collaborated with Sagar Mitra, IIT Bombay’s Professor in the Department of Energy Science and Engineering.

“IIT Bombay’s team is well known in LIB research and technology development. We are collaborating with IITB in several ways and in this project, IITB is actively participating in anode stabilization and the fabrication of cells with use of cathode material from Shiv Nadar University. The cell technology, development and its stabilization are done at IIT Bombay.

“Our lab scale data are ready (TRL -2/3) and we are looking for partner/financial assistance to develop this technology till TRL 6 in pouch format,” notes Lochab.

Bimlesh Lochab(1)

The capability of 3x energy density, coupled with being a significantly safer technology, holds the promise of accelerating the adoption of clean, battery-led energy.

The Lithium-Sulfur (Li-S) batteries developed by the team at Shiv Nadar University claims to be three times more energy efficient and cost-effective as compared to Lithium-ion batteries.

When asked to elaborate on this and other benefits of the battery, Lochab explains: “Li-S battery is not commercial yet, so it is difficult to compare the performance with any commercial Li-S product. However, if we compare the cell performance with the other reported literature, we are almost in the similar level of performance in terms of sulphur utilization, cyclic stability and sulphur loading and the cyclic performance. With our technology and understanding we can achieve 450 Wh/kg cells and 1000 cycles numbers at one-hour charging and discharging time.”

Apart from performance, Lochab says several other benefits are present in the current technology.

“The capability of 3x energy density, coupled with being a significantly safer technology, holds the promise of accelerating the adoption of clean, battery-led energy across multiple domains. For example, an electric car with a 400 km range using conventional Lithium-ion batteries can now quadruple its range to 1600 km on a single charge with this technology, while being compact in size and much safer to use than traditional Lithium-ion batteries. To put this in perspective, it could mean driving from Delhi to Mumbai on a single charge and still being left with power.

“The use of cardanol for Sulfur-based structures as an unconventional application to create cathode materials in this next generation Li-S battery technology has exhibited enhanced capacity retention (among the highest charge capacities reported) and longer battery life in a significantly smaller battery unit. The Sulfur for the battery is sourced from industrial waste and cardanol is sourced from bio-renewable feed-stock that is easily available, non-toxic and environmentally friendly.

“In addition, the research innovatively used eugenol (derived from clove oil) copolymer, which is also environmentally sustainable, halogen-free, flame-retardant, and reduces the combustible propensities, making the battery remarkably safe to use.”

This leads to the question whether or not the Li-S battery is more sustainable than the regular Li-ion batteries. For instance, does this technology help in cutting down the amount of rare-earth materials being used in the batteries? And then there comes the question about how easy it is to recycle.

“Yes, Li-S battery is more sustainable than the regular Li-ion batteries due to the utility of industrial waste, sulphur based copolymer as cathode,” Lochab answers.

“We have used naturally abundant phenol (cardanol, cashew nut shell liquid and eugenol: clove oil) based comonomer to copolymerize with elemental sulphur by inverse vulcanization. Overall process is scalable and cost effective. Current proposition eliminates the need of rare earth materials, which are currently essential for the functioning of the reported LIB. Recycling of Li-S may be easy comparatively as it is not a multicomponent system. Sulphur is more thermally labile and can be removed easily and is a waste product of petroleum industry.”

And that’s not all. According to Lochab, while this technology can be used for a whole range of industries such as consumer technology and drones, in the electric mobility sector alone it has a whole range of applications.

“Any application needs more energy density and one-hour charge-discharge time; we can apply them. A few are in our mind like long-range electric vehicles, heavy vehicles and military applications etc,” she says.

“Our proposition is to make LiS battery cells with 400-450 Wh/kg energy density at one-hour charge –discharge time and that is 3x of current LIB technology performance. We are targeting the performance enhancement in terms of cyclic stability and high charge-discharge time. LiS battery is well-known to work at lower temperature which is plus point here and higher temperature operations (60 deg C) strategy we are working now,” concludes Lochab.

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