Dr Mridula Dixit Bharadwaj

Understanding the Solvation Structure in Bulk Electrolyte Solutions

Understanding the relationship between the interaction of ions in solution with the solvation structure and its dynamics and the bulk properties like ionic conductivity, viscosity, etc is of considerable importance. Solute-solute, solute-solvent, and solvent-solvent interactions play a crucial role in determining the solvation structure and its dynamics. The selection of suitable electrolyte can greatly impact the performace of electrical energy storage devices.

Structural Transformation During Li/Na Insertion and Theoretical Cyclic Voltammetry of the δ-NH4V4O10 Electrode: A first-principles study

A double layer δ-NH4V4O10, due to its high energy storage capacity and excellent rate capability, is a very promising cathode material for Li-ion and Na-ion batteries for large-scale renewable energy storage in transportation and smart grids. While it possesses better stability, and higher ionic and electronic conductivity than the most widely explored V2O5, the mechanisms of its cyclability are yet to be understood.

Electrochemical Properties and First-Principle Analysis of Na x [M y Mn1-y ]O2 (M = Fe, Ni) Cathode

Sodium-ion batteries are the commercially and environmentally viable next-generation candidates for automobiles. Structural and electrochemical aspects are greater concerns towards the development of a stable cathode material. Selecting transition metals and their composition greatly influences charge order, superstructures, and different voltage plateaus. This, in turn, influences transport properties and cyclic performance. This article aims to study the electrochemical performance, diffusivity, and structural stability of Na x [M y Mn1−y ]O2 (M = Fe, Ni) as cathode.

Transition Metal Oxides as Cathodes for Li-ion battery: Structure, stability and substitution effects

First–principles DFT simulations are computationally demanding but are reasonably accurate in predicting properties of battery cathode materials. Properties relevant to selection of cathode
material include electrochemical potential, structural stability, energy/power density and cycle life etc. Computational screening of materials speeds up the process of material discovery by
saving on costs of experiments and time. In addition, it helps in developing correlation between properties and structural and chemical aspects. Here we analyze some of these aspects for the

Rare Earths Recovery from Secondary Resources: Opportunities, Challenges and Environmental impacts

Rare earths are not as rare as the name suggests, they are relatively abundant in the earth`s crust,
but their concentration is less in ore deposits, in particular heavy rare earths. Commercially,
REEs are extracted from the bastnasite, monazite and xenotime ores. The extraction of REEs
from mineral ore (primary source) is a complicated multi step process with a huge amount of
toxic wa ste released during the processes. The recovery of REEs from secondary sources such

Comparative analysis of electrochemical properties of LiMO2, LiMSiO4 and LiMPO4 (M=Fe, Co and Mn): A first principles study

Polyanion based cathode materials are most promising candidates for lithium ion batteries due to low cost, safety, environmental friendliness, etc. We performed first principles based DFT calculations to understand the stability, charge transfer mechanism and electrochemical performance of olivine phosphates, silicates and its comparison with the transition metal layered oxides based cathode materials. We have computed the changes in oxidation states using Bader method of topological analysis and charge re-distribution by analysis of partial density of electronic states.

A microscopic view of ion solvation in aqueous and non-aqueous electrolyte solutions from molecular dynamics simulations

Molecular dynamics simulations were performed to understand the ionic association and its effect on the structure and dynamics of ion solvation shell in aqueous and non-aqueous electrolyte solutions (water and methanol). The simulation results show that the probability of ion pairing depends on the interplay between ion-solvent interactions on the one hand, and Coulomb forces between ion and its counter-ion on the other hand.

Classical molecular dynamics and quantum abs-initio studies on lithium-intercalation in interconnected hollow spherical nano-spheres of amorphous Silicon

A high concentration of lithium, corresponding to charge capacity of ∼4200 mAh/g, can be intercalated in silicon. Unfortunately, due to high intercalation strain leading to fracture and consequent poor cyclability, silicon cannot be used as anode in lithium ion batteries. But recently interconnected hollow nano-spheres of amorphous silicon have been found to exhibit high cyclability. The absence of fracture upon lithiation and the high cyclability has been attributed to reduction in intercalation stress due to hollow spherical geometry of the silicon nano-particles.