Imperial College London

Dr Anisha Patel

Faculty of EngineeringDepartment of Mechanical Engineering

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anisha.patel

 
 
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City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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25 results found

Patel A, Lander L, Jyoti A, Bulman J, Lum J, Pople J, Hales A, Patel Y, Edge Jet al., 2024, Lithium-ion battery second life: pathways, challenges and outlook, Frontiers in Chemistry, ISSN: 2296-2646

Journal article

Vadhva P, Boyce AM, Patel A, Shearing PR, Offer G, Rettie AJEet al., 2023, Silicon-Based Solid-State Batteries: Electrochemistry and Mechanics to Guide Design and Operation., ACS Appl Mater Interfaces, Vol: 15, Pages: 42470-42480

Solid-state batteries (SSBs) are promising alternatives to the incumbent lithium-ion technology; however, they face a unique set of challenges that must be overcome to enable their widespread adoption. These challenges include solid-solid interfaces that are highly resistive, with slow kinetics, and a tendency to form interfacial voids causing diminished cycle life due to fracture and delamination. This modeling study probes the evolution of stresses at the solid electrolyte (SE) solid-solid interfaces, by linking the chemical and mechanical material properties to their electrochemical response, which can be used as a guide to optimize the design and manufacture of silicon (Si) based SSBs. A thin-film solid-state battery consisting of an amorphous Si negative electrode (NE) is studied, which exerts compressive stress on the SE, caused by the lithiation-induced expansion of the Si. By using a 2D chemo-mechanical model, continuum scale simulations are used to probe the effect of applied pressure and C-rate on the stress-strain response of the cell and their impacts on the overall cell capacity. A complex concentration gradient is generated within the Si electrode due to slow diffusion of Li through Si, which leads to localized strains. To reduce the interfacial stress and strain at 100% SOC, operation at moderate C-rates with low applied pressure is desirable. Alternatively, the mechanical properties of the SE could be tailored to optimize cell performance. To reduce Si stress, a SE with a moderate Young's modulus similar to that of lithium phosphorous oxynitride (∼77 GPa) with a low yield strength comparable to sulfides (∼0.67 GPa) should be selected. However, if the reduction in SE stress is of greater concern, then a compliant Young's modulus (∼29 GPa) with a moderate yield strength (1-3 GPa) should be targeted. This study emphasizes the need for SE material selection and the consideration of other cell components in order to optimize the performance of

Journal article

Vadhva P, Boyce AM, Hales A, Pang M-C, Patel AN, Shearing PR, Offer G, Rettie AJEet al., 2022, Towards optimised cell design of thin film silicon-based solid-state batteries via modelling and experimental characterisation, Journal of The Electrochemical Society, Vol: 169, Pages: 1-11, ISSN: 0013-4651

To realise the promise of solid-state batteries, negative electrode materials exhibiting large volumetric expansions, such as Li and Si, must be used. These volume changes can cause significant mechanical stresses and strains that affect cell performance and durability, however their role and nature in SSBs are poorly understood. Here, a 2D electro-chemo-mechanical model is constructed and experimentally validated using steady-state, transient and pulsed electrochemical methods. The model geometry is taken as a representative cross-section of a non-porous, thin-film solid-state battery with an amorphous Si (a-Si) negative electrode, lithium phosphorous oxynitride (LiPON) solid electrolyte and LiCoO2 (LCO) positive electrode. A viscoplastic model is used to predict the build-up of strains and plastic deformation of a-Si as a result of (de)lithiation during cycling. A suite of electrochemical tests, including electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique and hybrid pulse power characterisation are carried out to establish key parameters for model validation. The validated model is used to explore the peak interfacial (a-Siāˆ£LiPON) stress and strain as a function of the relative electrode thickness (up to a factor of 4), revealing a peak volumetric expansion from 69% to 104% during cycling at 1C. The validation of this electro-chemo-mechanical model under load and pulsed operating conditions will aid in the cell design and optimisation of solid-state battery technologies.

Journal article

Morgan LM, Islam MM, Yang H, O'Regan K, Patel AN, Ghosh A, Kendrick E, Marinescu M, Offer GJ, Morgan BJ, Islam MS, Edge J, Walsh Aet al., 2022, From Atoms to Cells: Multiscale Modeling of a LiNi<i><sub>x</sub></i>Mn<i><sub>y</sub></i>Co<i><sub>z</sub></i>O<sub>2</sub> Cathodes for Li-Ion Batteries, ACS ENERGY LETTERS, Vol: 7, Pages: 108-122, ISSN: 2380-8195

Journal article

Edge JS, O'Kane S, Prosser R, Kirkaldy ND, Patel AN, Hales A, Ghosh A, Ai W, Chen J, Yang J, Li S, Pang M-C, Bravo Diaz L, Tomaszewska A, Marzook MW, Radhakrishnan KN, Wang H, Patel Y, Wu B, Offer GJet al., 2021, Lithium ion battery degradation: what you need to know, Physical Chemistry Chemical Physics, Vol: 23, Pages: 8200-8221, ISSN: 1463-9076

The expansion of lithium-ion batteries from consumer electronics to larger-scale transport and energy storage applications has made understanding the many mechanisms responsible for battery degradation increasingly important. The literature in this complex topic has grown considerably; this perspective aims to distil current knowledge into a succinct form, as a reference and a guide to understanding battery degradation. Unlike other reviews, this work emphasises the coupling between the different mechanisms and the different physical and chemical approaches used to trigger, identify and monitor various mechanisms, as well as the various computational models that attempt to simulate these interactions. Degradation is separated into three levels: the actual mechanisms themselves, the observable consequences at cell level called modes and the operational effects such as capacity or power fade. Five principal and thirteen secondary mechanisms were found that are generally considered to be the cause of degradation during normal operation, which all give rise to five observable modes. A flowchart illustrates the different feedback loops that couple the various forms of degradation, whilst a table is presented to highlight the experimental conditions that are most likely to trigger specific degradation mechanisms. Together, they provide a powerful guide to designing experiments or models for investigating battery degradation.

Journal article

Paiva TO, Torbensen K, Patel AN, Anne A, Chovin A, Demaille C, Bataille L, Michon Tet al., 2020, Probing the Enzymatic Activity of Individual Biocatalytic <i>fd</i>-Viral Particles by Electrochemical-Atomic Force Microscopy, ACS CATALYSIS, Vol: 10, Pages: 7843-7856, ISSN: 2155-5435

Journal article

Torbensen K, Patel AN, Anne A, Chovin A, Demaille C, Bataille L, Michon T, Grelete Eet al., 2019, Immuno-Based Molecular Scaffolding of Glucose Dehydrogenase and Ferrocene Mediator on <i>fd</i> Viral Particles Yields Enhanced Bioelectrocatalysis, ACS CATALYSIS, Vol: 9, Pages: 5783-5796, ISSN: 2155-5435

Journal article

Patel AN, Kranz C, 2018, (Multi)functional Atomic Force Microscopy Imaging, ANNUAL REVIEW OF ANALYTICAL CHEMISTRY, VOL 11, Vol: 11, Pages: 329-350, ISSN: 1936-1327

Journal article

Chakri S, Patel AN, Frateur I, Kanoufi F, Sutter EMM, Tran TTM, Tribollet B, Vivier Vet al., 2017, Imaging of a Thin Oxide Film Formation from the Combination of Surface Reflectivity and Electrochemical Methods, ANALYTICAL CHEMISTRY, Vol: 89, Pages: 5303-5310, ISSN: 0003-2700

Journal article

Patel AN, Anne A, Chovin A, Demaille C, Grelet E, Michon T, Taofifenua Cet al., 2017, Scaffolding of Enzymes on Virus Nanoarrays: Effects of Confinement and Virus Organization on Biocatalysis, SMALL, Vol: 13, ISSN: 1613-6810

Journal article

Zhang G, Tan S-Y, Patel AN, Unwin PRet al., 2016, Electrochemistry of Fe3+/2+ at highly oriented pyrolytic graphite (HOPG) electrodes: kinetics, identification of major electroactive sites and time effects on the response, Physical Chemistry Chemical Physics, Vol: 18, Pages: 32387-32395, ISSN: 1463-9076

The electrochemistry of the Fe3+/2+ redox couple has been studied on highly oriented pyrolytic graphite (HOPG) samples that differ in step edge density by 2 orders of magnitude, to elucidate the effect of surface structure on the electron transfer (ET) kinetics. Macroscopic cyclic voltammetry measurements in a droplet-cell arrangement, highlight that the Fe3+/2+ process is characterised by slow ET kinetics on HOPG and that step edge coverage has little effect on the electrochemistry of Fe3+/2+. A standard heterogeneous ET rate constant of ∼5 × 10−5 cm s−1 for freshly cleaved HOPG was derived from simulation of the experimental results, which fell into the range of the values reported for metal electrodes, e.g. platinum and gold, despite the remarkable difference in density of electronic states (DOS) between HOPG and metal electrodes. This provides further evidence that outer-sphere redox processes on metal and sp2 carbon electrodes appear to be adiabatic. Complementary surface electroactivity mapping of HOPG, using scanning electrochemical cell microscopy, reveal the basal plane to be the predominant site for the Fe3+/2+ redox process. It is found that time after cleavage of the HOPG surface has an impact on the surface wettability (and surface contamination), as determined by contact angle measurements, and that this leads to a slow deterioration of the kinetics. These studies further confirm the importance of understanding and evaluating surface structure and history effects in HOPG electrochemistry, and how high resolution measurements, coupled with macroscopic studies provide a holistic view of electrochemical processes.

Journal article

Maddar FM, Lazenby RA, Patel AN, Unwin PRet al., 2016, Electrochemical oxidation of dihydronicotinamide adenine dinucleotide (NADH): comparison of highly oriented pyrolytic graphite (HOPG) and polycrystalline boron-doped diamond (pBDD) electrodes, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 18, Pages: 26404-26411, ISSN: 1463-9076

Journal article

Brasiliense V, Martinez-Marrades A, Patel AN, Berto P, Kuszelewicz R, Shi Y, Chen Y, Combellas C, Tessier G, Kanoufi Fet al., 2016, Holographic superlocalization of individual silver nanoparticle impacts in micro-electrochemical cells

Superlocalization holography is coupled to electrochemical detection in order to explore a variety of chemical systems. Nanoparticles oxidation is shown to be a complex reaction, where charge injection and particle dissolution are not necessarily simultaneous.

Conference paper

Brasiliense V, Patel AN, Martinez-Marrades A, Shi J, Chen Y, Combellas C, Tessier G, Kanoufi Fet al., 2016, Correlated Electrochemical and Optical Detection Reveals the Chemical Reactivity of Individual Silver Nanoparticles, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 138, Pages: 3478-3483, ISSN: 0002-7863

Journal article

Patel AN, Martinez-Marrades A, Brasiliense V, Koshelev D, Besbes M, Kuszelewicz R, Combellas C, Tessier G, Kanoufi Fet al., 2015, Deciphering the Elementary Steps of Transport-Reaction Processes at Individual Ag Nanoparticles by 3D Super localization Microscopy, NANO LETTERS, Vol: 15, Pages: 6454-6463, ISSN: 1530-6984

Journal article

Zhang G, Kirkman PM, Patel AN, Cuharuc AS, McKelvey K, Unwin PRet al., 2014, Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 136, Pages: 11444-11451, ISSN: 0002-7863

Journal article

Parker AS, Patela AN, Al Botros R, Snowden ME, McKelvey K, Unwin PR, Ashcroft AT, Carvell M, Joiner A, Peruffo Met al., 2014, Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel, JOURNAL OF DENTISTRY, Vol: 42, Pages: S21-S29, ISSN: 0300-5712

Journal article

Batchelor-McAuley C, Martinez-Marrades A, Tschulik K, Patel AN, Combellas C, Kanoufi F, Tessier G, Compton RGet al., 2014, Simultaneous electrochemical and 3D optical imaging of silver nanoparticle oxidation, CHEMICAL PHYSICS LETTERS, Vol: 597, Pages: 20-25, ISSN: 0009-2614

Journal article

Patel AN, Tan S-Y, Miller TS, Macpherson JV, Unwin PRet al., 2013, Comparison and Reappraisal of Carbon Electrodes for the Voltammetric Detection of Dopamine, ANALYTICAL CHEMISTRY, Vol: 85, Pages: 11755-11764, ISSN: 0003-2700

Journal article

Patel AN, Tan S-Y, Unwin PR, 2013, Epinephrine electro-oxidation highlights fast electrochemistry at the graphite basal surface, CHEMICAL COMMUNICATIONS, Vol: 49, Pages: 8776-8778, ISSN: 1359-7345

Journal article

Patel AN, Unwin PR, Macpherson JV, 2013, Investigation of film formation properties during electrochemical oxidation of serotonin (5-HT) at polycrystalline boron doped diamond, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 15, Pages: 18085-18092, ISSN: 1463-9076

Journal article

Patel AN, McKelvey K, Unwin PR, 2012, Nanoscale Electrochemical Patterning Reveals the Active Sites for Catechol Oxidation at Graphite Surfaces, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 20246-20249, ISSN: 0002-7863

Journal article

Patel AN, Collignon MG, O'Connell MA, Hung WOY, McKelvey K, Macpherson JV, Unwin PRet al., 2012, A New View of Electrochemistry at Highly Oriented Pyrolytic Graphite, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 20117-20130, ISSN: 0002-7863

Journal article

Lai SCS, Patel AN, McKelvey K, Unwin PRet al., 2012, Definitive Evidence for Fast Electron Transfer at Pristine Basal Plane Graphite from High-Resolution Electrochemical Imaging, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 51, Pages: 5405-5408, ISSN: 1433-7851

Journal article

Hutton LA, Vidotti M, Patel AN, Newton ME, Unwin PR, Macpherson JVet al., 2011, Electrodeposition of Nickel Hydroxide Nanoparticles on Boron-Doped Diamond Electrodes for Oxidative Electrocatalysis, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 115, Pages: 1649-1658, ISSN: 1932-7447

Journal article

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