Seminar Details

Seminar Title
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Development of High-voltage oxide cathodes for lithium-ion batteries
Seminar Type
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Registration Seminar
Department
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Ceramic Engineering
Speaker Type
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Student
Speaker Name
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ABHISHEK KUMAR ( RollNo : 519CR1003)
Date  &  Time
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08 Apr 2021  11 AM
Venue
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Online mode through MS Team (Team code:z2sjy3y)
Contact
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Prof. Partha Saha
Abstract
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The LiCoO2 is a commercially established cathode for Li-ion batteries (LIBs) offering gravimetric capacity ~138 mAhg−1. However, the depleted global reserve of cobalt-bearing compounds and the exorbitant cost pushes toward identifying Co-free or low Co-containing cathodes. In this regard, LiNiO2 remains very attractive, offering high gravimetric capacity (~240 mAhg−1). However, similar ionic radii of Ni2+ and Li+ lead to Li/Ni cation mixing during (de)intercalation and Ni2+ ion migrating to the Li sites. The above factor is detrimental, reduces the rate capability, and gives rise to residual surface Li2CO3, which is a serious drawback. In order to prevent the cation mixing problem, layered oxide cathodes are partially substituted with Co, Mn, Al, Mg, and Ti at the expense of Ni. In this regard, transition metal-transition metal (TM-TM) interactions play an important role towards the phase stability in layered Ni-rich LixNi1-y-zCoyMnzO2 (NCM) cathodes. Ni ion provides a higher capacity by Ni3+/Ni4+ redox reaction, while Co ion enhances the rate performance, and Mn ion helps sustain structural stability. Ni contents in NCM cathode generally varies from NCM333 (x=1, y and z = 0.33) to NCM811 (x = 1, y and z = 0.1) with a capacity higher than 200 mAhg−1, but sharply deteriorate phase stability when Ni ≥ 80%. As a result, developing Ni-rich layered LixNi1-y-zMnyAlzO2 (NMA) oxide cathode with an optimized Co-free composition other than NCM is paramount. Besides, the present work also deals with the selection of concentration gradient and core-shell NCM cathode involving an outer shell rich in Mn content and an inner core rich in Ni content for high voltage LIBs. It is anticipated that Mn-rich composition in the surface will contribute the thermal stability, and the Ni-rich composition inside the core will provide high discharge capacity-achieving optimal performance in LIBs.