Radhika Krishna Hema Email & Phone Number

Ulm, Bw, De

Ulm, Baden-Württemberg, Germany

Developing sodium-ion batteries for cost-effective and sustainable stationary energy storage Supervisor: Dr. Alberto Varzi/Passerini group• Designing and testing water-in-salt electrolyte (WiSE) mixtures for sodium-ion batteries• Benchmarking with SoA organic electrolytes• Attempts at enhancing conductivity, ESW and SEI formation ability via interphase tuning and additives• Understanding SEI formation mechanisms, parasitic reactions, solvation structures, ionic interactions and conductivity routes• Evaluating the reaction kinetics at the interphases and their electrochemical compatibility with suitable current collectors, cell types and anode/cathode matrices• Fabricating full cells and lab-scale prototypes through aging tests on optimised electrode/electrolyte combinations

Uppsala County, Sweden

Decoding the electrode/electrolyte interfaces and interphases in lithium-ion batteries using operando ambient pressure photoelectron spectroscopy (APPES)Main Supervisor: Dr. Maria Hahlin[LOA from April 2022 - August 2022]• Introduced to characterisation of electrode/electrolyte interfaces and interphases in lithium-ion battery electrodes via operando ambient pressure photoelectron spectroscopy (APPES)• Gained practical insights on probing the electrochemical potential (electrostatic+chemical) distribution over the interface under simulated operando conditions and voltage depth profiling• Acquired a lead-in to APPES analysis [via following the KE drops (signal from electrolyte/electrode/electrolyte gas) with varying external potentials and correlating the potential profiles to the interfacial redox/EDL/diffusion processes]• Acquainted with synchrotron radiation facilities at HIPPIE (three electrode APPES electrochemical cell) and FLEXPES beamlines of MAX IV Laboratory, Lund, Sweden

Trivandrum, Kerala, India

Role of intrinsic defects in carbon based materials for electrocatalytic oxygen reductionSupervisor: Dr. A. Muthukrishnan• Reviewed the recent advancements in defective carbons as ORR catalysts and intrinsic (topological) defects in carbon systems• Designed and fabricated an intrinsic defects-rich carbon-based ORR catalyst with little to no contribution from dopants and heteroatoms• Adopted an intrinsically doped composite (assisted with a carbon support and a porogen/dehydrating agent) as the precursor in an attempt to enact the defect mechanism• Familiarised with carbon domains (hydrothermal synthesis, pyrolysis), material characterisation (Raman spectroscopy, TGA/DTA, XPS (CasaXPS for analysis), XRD, SEM-EDAX), ORR (CV, LSV using RRDE), graphing and analysis (VersaStudio, Origin)

Trivandrum, Kerala, India

Hard carbons as sodium-ion battery anodes: A mechanistic analysis of sodium storageSupervisor: Prof. M. M. Shaijumon• Documented a desk research on contradicting reports of Na-ion charge storage mechanism in hard carbon (HC) sodium-ion battery anodes• Framed and executed a study to decode the mechanistic behaviour of lignocellulosic biomass derived HCs via controllable tuning of nanoporosity• Investigated the structural and electrochemical transformations upon sodiation/desodiation via GCPL, CV, EIS, BET, TGA, SAXS (contribution from closed porosity), XRD and Raman spectroscopy• Exposed to HC synthesis (tubular furnace), glove box, battery fabrication (coin cell, pouch cell) and disassembling, cell testing (Bio-Logic), graphing and analysis (EC-Lab, Origin)

Bangalore, India

Redox active cobalt coordinated conjugated microporous polymer for oxygen evolution and reduction applicationsSupervisor: Prof. Tapas K. Maji• Synthesised and characterised a cobalt doped redox active conjugated microporous polymer (CMP) as a bifunctional catalyst for OER and ORR• Familiarised with organic synthesis, thin layer chromatography, column chromatography, material characterisation (FTIR, TGA, PXRD, N2 adsorption, TEM, FESEM/EDX, elemental mapping, ss-NMR), OER and ORR (EIS, CV, LSV, chronoamperometry using RDE, RRDE), graphing and analysis (Autolab, Origin, Chemdraw)

Hyderabad, India

(A) Development of an in situ impedance measurement setup with tunable humidity and temperatureSupervisor: Dr. T. N. Narayanan• Designed and implemented an experimental layout with independent provisions for simultaneously controlling temperature and relative humidity to measure impedance and thereby the ionic conductivities of ion exchange membranes• Focused on increasing the range of attainable hydration levels while maintaining optimised flow rates at high temperatures• Tested the structural efficacy by analysing the trends in conductivities of Nafion 117 and Fumasep 50• Introduced to control loop feedback equipments (PID temperature controller) and 2-electrode EIS(B) Electrochemical sensing studies on MoS2Supervisor: Dr. T. N. Narayanan• Executed voltammetric analyses on MoS2/GC and benzyl viologen/MoS2/GC systems• Refined prior experience in electrode preparation and 3-electrode cells (CHI workstation/analyser)

Kochi, Kerala, India

Electrooxidation of dopamine at CoNP-pHANSA modified electrode: A sensitive approach to its voltammetric determinationSupervisor: Dr. K. Girish Kumar• Developed a voltammetric dopamine sensor using a GCE modified with cobalt nano/poly(hyroxy amino naphthalene sulphonic acid) composite• Optimised the sensor's performance characteristics (supporting electrolyte, pH of supporting electrolyte, thickness of polymer film, dopamine concentration, scan rate, interference study)• Successfully ascertained the reliability of the developed sensor in real-life samples (in artificial blood serum, artificial urine and artificial cerebrospinal fluid)• Exposed to electrochemistry basics, electrode preparation, electrodeposition, electropolymerisation, voltammetric sensing (CV, SWV), 3-electrode measurements (SP300 Potentiostat)

Doctor Of Philosophy - Phd

Bs-Ms Dual Degree (Bachelor Of Science And Master Of Science), Major In Chemistry, Minor In Physics

Activities and Societies: • Anchored & part of the organizing team: Industry-Academia Conclave on Hydrogen & Fuel Cells (2020) sponsored.