<p dir="ltr">The thesis goal was to design a quasi-solid-state battery electrolyte, which was optimized to function at ambient as well as low temperatures. In the first project, an array of quasi-solid-state electrolytes were developed and compared. A series of electrochemical, spectroscopic, and thermal experiments in addition to imaging techniques determined a top performer as well as elucidated possible mechanistic explanations. This systematic study attempted to validate literature conclusions about the failure mechanisms governing batteries (solid-state batteries) at ultralow temperatures, while also offering hypothesis driven additional insight. The optimized electrolyte, which will be deemed as CSPE@2MMeTHF, performed well for several key reasons, traced to the co-solvent used (Me-THF), the salt concentration, and its formation of a stable and suitable cathode-electrolyte interphase. It was able to perform well at 25 °C, and down to -25 °C. The second part of the work, focused on further optimizing the electrolyte by removing a ‘polymer wetting/soaking’ step, removing a ceramic component, and pairing it with a recently discovered anodic electrode material. Given that narrowing the research gap for low temperatures requires both electrolyte and electrode design, it was important to consider this aspect of the problem as well. The cathodic electrode used for the first project, traditionally performs poorly at low temperatures, allowing for a suitable experimental control for the electrolyte. However, the new anodic electrode had two ways of storing lithium ions, as opposed to just one in the former, making it an attractive option for the stated goal of a low-temperature solid-state battery. This second project is akin to a ‘proof-of-concept’ work and there is much more room for further study, especially in preparing a full cell with the aforementioned electrodes cathode (LFP) and anode (NbWO) with the second SPE@51DMMeT electrolyte. In summary, this thesis shows method design to prepare solid-state electrolytes with portion of liquid, two successfully developed electrolyte systems for low temperatures, and a rigorous discussion of factors that affect electrochemical performance. Demonstrated research activities are of great value to defense as the current lithium-ion batteries does not perform well at subzero temperatures.</p>

Rechargeable batteries have already conquered the market of portable electronics (i.e., mobile phones and laptops) and are set to further enable the large-scale deployment of electric vehicles and hybrid electric vehicles in a not too distant future. In this context, a deeper understanding of the fundamental processes governing the electrochemical behavior of electrode materials for batteries is required for further development of these applications. The aims of the work described in this thesis have been to investigate how electrochemical properties and structural properties of novel electrode materials relate to each other. In this sense, electrochemical characterization, structural analysis using XRD and their combined simultaneous use via in operando XRD experiments have played a crucial part. The investigations showed that: Two oxohalides, Ni3Sb4O6F6 and Mn2Sb3O6Cl, react with Li-ions in a complex manner involving different types of reaction mechanisms at low voltages in Li half cells. In operando XRD show that both of these materials are reduced in a conversion reaction via an in situ formation of nanocomposites, which proceed to react reversibly with Li-ions in a combination of alloying and conversion reactions. Carbon-coated Na2Mn2Si2O7 was synthesized and characterized as a possible positive electrode material for non-aqueous Na-ion batteries. DFT calculations point to a structural origin of the modest electrochemical behavior of this material. It is suggested that structural rearrangements upon desodiation are associated with large overpotentials. It is demonstrated via an in operando synchrotron XRD study that Fe(CN)6 vacancies in copper hexacyanoferrate (CuHCF) play an important role in the electrochemical behavior toward Zn2+ in an aqueous CuHCF/Zn cell. Furthermore, manganese hexacyanomanganate (MnHCM) is shown to react reversibly with Li+, Na+ and K+ in non-aqueous alkali metal half cells. In contrast to CuHCF, which is a zero-strain material, MnHCM undergoes a series of structural transitions (from monoclinic to cubic) during electrochemical cycling.

<p dir="ltr">This dissertation addresses the significant challenge of enhancing the performance of lithium-ion batteries (LIBs) in extremely low-temperature environments, which is critical for applications in defense and space exploration. By innovating both electrolyte formulations and electrode materials, this research extends the operational boundaries of LIBs to temperatures below -100 ℃. </p>

<p dir="ltr">Lithium-ion (Li-ion) batteries are promising electrochemical energy storage and conversion systems to drive the rechargeable world toward a sustainable future. Following the breakthrough of material innovations, advanced Li-ion batteries have significantly mitigated the range and lifetime anxieties of electric vehicles (EVs) and consumer electronics. Nevertheless, state-of-the-art Li-ion chemistries still suffer from several defects, such as rapid degradations under abusive or fast-charge scenarios and unfavorable high thermal instabilities. Essentially, aging mechanisms and safety hazards of Li-ion cells are strongly coupled events. The cell safety factors are most likely to be deteriorated as degradation progresses, making the cell less safe after a long-term deployment. In this thesis, we comprehensively investigate thermo-electrochemical interactions on the safety of Li-ion batteries. Fundamental principles of Li-ion batteries, basic knowledge about material-level thermal instabilities at electrode-electrolyte interphases, thermal characterization approaches, and thermal runaway mechanisms under abusive scenarios are fully overviewed. Thermally unstable characteristics of key cell components, including inter-electrode crosstalk as a result of oxygen liberation from cathode lattice structures, significant electric energy release from massive internal short circuit due to separator collapse, anode-centric lithium-plating-induced early exotherm, and silicon-dopant-driven thermal risks of composite anodes, are specifically discussed to understand their critical role in accelerating cell-level thermal runaway catastrophes. Aging pathways of Li-ion cells under off-normal conditions, particularly overdischarge and fast charging, are thoroughly elucidated using a promising reference electrode architecture, which effectively deconvolutes the electrode behaviors from the complex full-cell performance for precise identification of the root causes in cell failure. Given the profound revelation of degradation-safety sophistication in various Li-ion chemistries, corresponding mitigation and prevention strategies are proposed to maximize cell lifetime and reliability. This thesis provides new insights into aging and safety diagnostics of cutting-edge Li-ion batteries, taking one step further in the online monitoring of battery state of health to develop adaptive battery management systems.</p>

The chemical element carbon plays a key role in the 21st century. “The new carbon age” is associated with the global warming due to increasing carbon dioxide emissions. The latter are a major consequence of the continued combustion of fossil fuels for energy generation. However, carbon is also one key component to overcome these problems. Especially porous carbon materials are highly attractive for many environmentally relevant applications. These materials provide high specific surface area, high pore volume, thermal/chemical stability, and high electrical conductivity. They are promising candidates for the removal of carbon dioxide or other environmentally relevant gases from exhaust gas mixtures. Furthermore, porous carbons are used in electrochemical energy storage devices (e.g. batteries or electrochemical capacitors). The performance of the materials in these applications depends on their pore structure. Hence, precise control over the pore size and the pore geometry is important to achieve. Besides a high specific surface area (SSA) and a well-defined pore size, pore accessibility must be ensured because the surface must be completely available. If the porous carbons exhibit ink-bottle pores, the high surface area is useless because the guest species do not reach the pore interior. Therefore, carbon materials with hierarchical pore structure are attractive. They combine at least two different pore systems of different size which contribute with their individual advantages. While smaller pores provide large specific surface area, larger pores ensure efficient mass transport. Numerous methods for the targeted synthesis of carbide-derived carbon materials (CDCs) with hierarchical pore architectures were developed within this thesis (Figure 1). CDCs are produced by the extraction of metal- or semi-metal atoms from carbide precursors leading to the formation of a microporous carbon network with high specific surface area. PolyHIPE-CDCs with porosity on three hierarchy levels and total pore volumes as high as 8.5 cm3/g were prepared by a high internal phase emulsion technique. CO2 activation increases the SSA to values above 3100 m2/g. These materials are promising for the filtration of non-polar organic compounds from gas mixtures. CDC nanospheres with diameters below 200 nm were obtained from polycarbosilane-based miniemulsions. They show high capacitance of up to 175 F/g in symmetrical EDLCs in 1 M H2SO4 aqueous electrolyte. Besides such emulsion techniques, the hard-templating concept (also referred to as nanocasting) was presented as an efficient approach for the synthesis of CDC mesofoam powders and meso-macroporous CDC monoliths starting from silica templates and polycarbosilane precursors. As a wide range of pore sizes is approachable, the resulting materials are highly versatile in terms of application. Due to their high nanopore volume, well-defined mesopores and large SSA, they show outstanding properties as electrode materials in EDLCs or in Li-S batteries as well as high and rapid uptake in gas adsorption processes. CDC aerogels were produced by pyrolysis and high-temperature chlorine treatment of cross-linked polycarbosilane aerogels. These materials can be tailored for efficient CO2 adsorption and show outstanding performance in EDLC electrodes at high current densities of up to 100 A/g due to the very short electron diffusion pathways within the aerogel-type pore system. It was further shown that CDCs can be combined with mesopores by the sacrificial template method starting from PMMA particles as the pore-forming material. The use of highly toxic hydrofluoric acid for template removal and large amounts of organic solvents as typical for hard- and soft-templating approaches can be overcome. SSAs and total pore volumes of 2434 m2/g and 2.64 cm3/g are achieved ensuring good performance of PMMA-CDCs in Li-S batteries cathodes. Besides the characterization of CDCs in real energy storage devices and adsorption processes, their use as model substances in energy- and environmentally relevant applications was part of this thesis. The questions “How does it work?” and “What do we need?” must be clearly answered before any material can be tailored under the consideration of economic and ecological perspectives. The high potential of CDCs for this purpose was shown in this thesis. These carbons were used as model substances in combination with nuclear magnetic resonance (NMR) techniques to get a detailed understanding of the adsorption processes on porous carbon surfaces. However, such investigations require the use of model substances with a tailored and well-defined pore structure to clearly differentiate physical states of adsorbed species and to understand fundamental mechanisms. The characterization of the interaction of electrolyte molecules with the carbon surface was performed with solid-state NMR experiments. The materials were also studied in the high-pressure adsorption of 129Xe using an in-situ NMR technique. Both NMR studies enable the analysis of ions or gas atoms adsorbed on the carbon surface on an atomic level and experimentally demonstrate different strength of interaction with pores of variable size and connectivity. In addition, the novel InfraSORP technology was used for the investigation of the thermal response of CDCs and templated carbon and carbide materials during n-butane adsorption. These model systems lead to a more profound understanding of this technique for the rapid characterization of porous materials. The Kroll-Carbon (KC) concept is a highly attractive alternative for the synthesis of well-defined carbons on the large scale. In this technique, the porous materials are produced by the reductive carbochlorination reaction between oxidic nanoparticles and a surrounding carbon matrix. First KC materials were produced with high SSA close to 2000 m2/g and total pore volumes exceeding 3 cm3/g. This method was established with template particles of various dimensions as well as by using various types of oxides (silica, alumina, titania). Hence, porous carbon materials with various textural parameters are approachable. The first generation of KCs is promising for the use in Li-S battery cathodes and as electrode materials in EDLCs.

Les supercondensateurs sont des dispositifs de stockage électrochimique de l’énergie ayant été récemment mis au point et possédant des performances intermédiaires entre les condensateurs diélectriques et les batteries. Leurs intéressantes valeurs de densité d’énergie et de puissance, conjuguées à leur excellente durée de vie et à leur miniaturisation facilité rendent ces composants prometteurs pour des micro-dispositifs électroniques, tels des micro-capteurs autonomes ou des implants médicaux.Le silicium nanostructuré par CVD a prouvé être un remarquable matériau d’électrode de supercondensateur, pour des applications miniaturisées, lors de récents travaux. L’excellent contrôle de la morphologie et des propriétés électroniques permis par la synthèse montante de nano-fils et nano-arbres de silicium, ainsi que la grande stabilité électrochimique et thermique de ce matériau font des nanostructures de silicium obtenues par synthèse montante une excellente plate-forme pour des micro-supercondensateurs.La présente thèse s’attache à explorer plusieurs voies d’amélioration et d’utilisation des nano-fils et nano-arbres de silicium. Une étude systématique de l’optimisation des nanostructures a été conduite, permettant d’améliorer largement les performances précédemment établies. Ensuite, une fonctionnalisation par des couches minces d’alumines utilisant la technique d’ALD a permis d’accroitre largement la plage de tensions d’utilisation des supercondensateurs, et d’augmenter leur stabilité électrochimique. Enfin, la croissance « sur-puce », ainsi que l’étude de la stabilité en température des dispositifs ont été effectuées, laissant entrevoir d’importantes perspectives d’applications. / Supercapacitors are electrochemical energy storage devices which have been recently developed, and possess intermediate performances between dielectric capacitors and batteries. These components exhibit interesting power and energy densities, combined with an exceptional cycle life and an easy miniaturization. Supercapacitors are thus envisioned as energy storage solutions for electronic micro-devices, such as autonomous micro-sensors or implantable medical devices.In recent studies, CVD nanostructured silicon proved to be an excellent electrode material candidate for micro-supercapacitor applications. Bottom-up synthesis allows an exceptional control of the morphology and electrical properties of the obtained silicon nano-wires and nano-trees. Moreover, the nanostructured electrodes possess superior electrochemical and temperature stability. These arguments lead to consider silicon as an excellent platform for micro-supercapacitors applications.This PhD thesis details various ways to improve and use silicon nano-wires and nano-trees. The nanostructures have been subjected to a systematic optimization study, yielding a significant increase of the electrochemical performances of the electrodes, compared to previously published studies. In addition, surface functionalization using thin ALD alumina layers permitted a considerable increase of the supercapacitor voltage window and an improved electrochemical stability. Finally, “on-chip” nanostructure growth, and temperature stability studies of the device were conducted, opening a broad field of improvements and potential uses for these silicon nanostructures.

Actuellement, le développement à grande échelle des piles à combustible à membrane échangeuse de protons est limité par l’utilisation importante de platine ainsi que par une faible durabilité des dispositifs. Les électrodes conventionnelles, dénommées Pt/C, sont constituées de nanoparticules de platine déposées sur un support composé de nanoparticules de carbone. Le but de cette thèse est de proposer, élaborer et tester en pile à combustible complète des nanostructures composées de nanotubes de platine autosupportés afin d’augmenter la durée de vie des dispositifs et de réduire la quantité de platine utilisée. Afin de réaliser de telles nanostructures, un moule d’alumine nanoporeuse constitué de nanopores verticaux est élaboré par oxydation électrochimique d’aluminium. Cette matrice de nanopores permet de réaliser une croissance confinée de nanotubes de platine par évaporation de métal sous vide ou par des dépôts électrochimiques. Une membrane de Nafion® est par la suite pressée à chaud et l’alumine est dissoute. Des nanotubes de platine autosupportés sont ainsi obtenus à la surface de la membrane. Afin de comprendre le fonctionnement de ces électrodes en pile à combustible complète, une méthode de quantification des pertes limitant les performances d’électrodes standards de Pt/C a été utilisée. La nanostructuration des électrodes permet d’augmenter significativement la durée de vie des dispositifs et de diminuer les pertes de transport d’oxygène. La principale limitation mise en évidence est des pertes cinétiques importantes en raison de la faible surface spécifique de platine développée. / The two main drawbacks of Proton Exchange Membrane Fuel Cells (PEMFC) are the low electrode durability and the high platinum loading (electrocatalyst for oxygen reduction reaction). Currently, PEMFC electrodes, named as Pt/C, are made of platinum nanoparticles supported by carbon nanoparticles. The aim of this PhD work is to propose, elaborate and test in complete fuel cell new electrode nanostructure consists in self-supported platinum nanotubes. We target a reduction in the platinum loading and an increase in the electrode durability. In order to control nanostructure geometries, a porous alumina mold is used. This template is obtained by electrochemical anodization and vertically aligned nanopores are obtained. Platinum is subsequently deposited onto pore walls by e-beam evaporation or electrochemical deposition processes. After the hot pressing of the Nafion® proton exchange membrane, the porous alumina mold is etched and platinum nanotubes are stuck and self-supported onto the membrane. A part of this work is dedicated to the quantification of performances losses of Pt/C electrodes and nanostructured electrodes in complete fuel cell test operating conditions. Nanostructured electrodes exhibit high durability and easy oxygen access on catalyst surface compared to Pt/C electrodes. However, some losses kinetics remains due to the low catalyst specific area.

A Comprehensive review of literature on electrode materials for lithium-ion batteries is provided in Chapter 1 of the thesis. Chapter 2 deals with the studies on porous, sub-micrometer size LiNi1/3Co1/3O2 as a positive electrode material for Li-ion cells synthesized by inverse microemulsion route and polymer template route. The electromechanical characterization studies show that carbon-coated LiNi1/3Co1/3O2 samples exhibit improved rate capability and cycling performance. Furthermore, it is anticipated that porous LiNi1/3Co1/3O2 could be useful for high rates of charge-discharge cycling. Synthesis of sub-micrometer size, porous particles of LiNi1/3Co1/3O2 using a tri-block copolymer as a soft template is carried out. LiNi1/3Co1/3O2 sample prepared at 900ºC exhibits a high rate capability and stable capacity retention of cycling. The electrochemical performance of LiNi1/3Co1/3O2 prepared in the absence of the polymer template is inferior to that of the sample prepared in the presence of the polymer template. Chapter 4 involves the synthesis of sub-micrometer size particles of LiMn2O4 in quaternary microemulsion medium. The electrochemical characterization studies provide discharge capacity values of about 100 mAh g-1 at C/5 rate and there is moderate decrease in capacity by increasing the rate of charge-discharge cycling. Studies also include charge-discharge cycling as well as ac impedance studies in temperature range from -10 to 40º C. Chapter 5 reports the synthesis of nano-plate LiFePO4 by polyol route starting from two reactants, namely, FePO42H2O and LiOH.2H2O. The electrodes fabricated out of nano-plate of LiFePO4 exhibit a high electrochemical activity. A stable capacity of about 155 mAh g-1 is measured at 0.2 C over 50 charge-discharge cycles. Mesoporous LiFePO4/C composite with two sizes of pores is prepared for the first time via solution-based polymer template technique. The precursor of LiFePO4/C composite is heated at different temperatures in the range from 600 to 800ºC to study the effect of crystalllinity, porosity and morphology on the electrochemical performance. The compound obtained at 700ºC exhibits a high rate capability and stable capacity retention on cycling with pore size distribution around 4 and 46nm. In Chapter 6, the electrochemical characterization of LiMn2O4 in an aqueous solution of 5 M LiNO3 is reported. A typical cell employing LiMn2O4 as the positive electrode and V2O5 as the negative electrode was assembled and the characterized by charge-discharge cycling in 5 M LiNO3 aqueous electrolyte. Furthermore, it is shown that Li+-ion in LiMn2O4 can be replaced by other divalent ions resulting in the formation of MMn2O4 (M = Ca, Mg, Ba and Sr) in aqueous M(NO3)2 electrolytes by subjecting LiMn2O4 electrodes to cyclic voltametry. Cyclic voltammetry and chronopotentiometry studies suggest that MMn2O4 can undergo reversible redox reaction by intercalation/deintercalation of M2+-ions in aqueous M(NO3)2 electrolytes.

The chemical element carbon plays a key role in the 21st century. “The new carbon age” is associated with the global warming due to increasing carbon dioxide emissions. The latter are a major consequence of the continued combustion of fossil fuels for energy generation. However, carbon is also one key component to overcome these problems. Especially porous carbon materials are highly attractive for many environmentally relevant applications. These materials provide high specific surface area, high pore volume, thermal/chemical stability, and high electrical conductivity. They are promising candidates for the removal of carbon dioxide or other environmentally relevant gases from exhaust gas mixtures. Furthermore, porous carbons are used in electrochemical energy storage devices (e.g. batteries or electrochemical capacitors). The performance of the materials in these applications depends on their pore structure. Hence, precise control over the pore size and the pore geometry is important to achieve. Besides a high specific surface area (SSA) and a well-defined pore size, pore accessibility must be ensured because the surface must be completely available. If the porous carbons exhibit ink-bottle pores, the high surface area is useless because the guest species do not reach the pore interior. Therefore, carbon materials with hierarchical pore structure are attractive. They combine at least two different pore systems of different size which contribute with their individual advantages. While smaller pores provide large specific surface area, larger pores ensure efficient mass transport. Numerous methods for the targeted synthesis of carbide-derived carbon materials (CDCs) with hierarchical pore architectures were developed within this thesis (Figure 1). CDCs are produced by the extraction of metal- or semi-metal atoms from carbide precursors leading to the formation of a microporous carbon network with high specific surface area. PolyHIPE-CDCs with porosity on three hierarchy levels and total pore volumes as high as 8.5 cm3/g were prepared by a high internal phase emulsion technique. CO2 activation increases the SSA to values above 3100 m2/g. These materials are promising for the filtration of non-polar organic compounds from gas mixtures. CDC nanospheres with diameters below 200 nm were obtained from polycarbosilane-based miniemulsions. They show high capacitance of up to 175 F/g in symmetrical EDLCs in 1 M H2SO4 aqueous electrolyte. Besides such emulsion techniques, the hard-templating concept (also referred to as nanocasting) was presented as an efficient approach for the synthesis of CDC mesofoam powders and meso-macroporous CDC monoliths starting from silica templates and polycarbosilane precursors. As a wide range of pore sizes is approachable, the resulting materials are highly versatile in terms of application. Due to their high nanopore volume, well-defined mesopores and large SSA, they show outstanding properties as electrode materials in EDLCs or in Li-S batteries as well as high and rapid uptake in gas adsorption processes. CDC aerogels were produced by pyrolysis and high-temperature chlorine treatment of cross-linked polycarbosilane aerogels. These materials can be tailored for efficient CO2 adsorption and show outstanding performance in EDLC electrodes at high current densities of up to 100 A/g due to the very short electron diffusion pathways within the aerogel-type pore system. It was further shown that CDCs can be combined with mesopores by the sacrificial template method starting from PMMA particles as the pore-forming material. The use of highly toxic hydrofluoric acid for template removal and large amounts of organic solvents as typical for hard- and soft-templating approaches can be overcome. SSAs and total pore volumes of 2434 m2/g and 2.64 cm3/g are achieved ensuring good performance of PMMA-CDCs in Li-S batteries cathodes. Besides the characterization of CDCs in real energy storage devices and adsorption processes, their use as model substances in energy- and environmentally relevant applications was part of this thesis. The questions “How does it work?” and “What do we need?” must be clearly answered before any material can be tailored under the consideration of economic and ecological perspectives. The high potential of CDCs for this purpose was shown in this thesis. These carbons were used as model substances in combination with nuclear magnetic resonance (NMR) techniques to get a detailed understanding of the adsorption processes on porous carbon surfaces. However, such investigations require the use of model substances with a tailored and well-defined pore structure to clearly differentiate physical states of adsorbed species and to understand fundamental mechanisms. The characterization of the interaction of electrolyte molecules with the carbon surface was performed with solid-state NMR experiments. The materials were also studied in the high-pressure adsorption of 129Xe using an in-situ NMR technique. Both NMR studies enable the analysis of ions or gas atoms adsorbed on the carbon surface on an atomic level and experimentally demonstrate different strength of interaction with pores of variable size and connectivity. In addition, the novel InfraSORP technology was used for the investigation of the thermal response of CDCs and templated carbon and carbide materials during n-butane adsorption. These model systems lead to a more profound understanding of this technique for the rapid characterization of porous materials. The Kroll-Carbon (KC) concept is a highly attractive alternative for the synthesis of well-defined carbons on the large scale. In this technique, the porous materials are produced by the reductive carbochlorination reaction between oxidic nanoparticles and a surrounding carbon matrix. First KC materials were produced with high SSA close to 2000 m2/g and total pore volumes exceeding 3 cm3/g. This method was established with template particles of various dimensions as well as by using various types of oxides (silica, alumina, titania). Hence, porous carbon materials with various textural parameters are approachable. The first generation of KCs is promising for the use in Li-S battery cathodes and as electrode materials in EDLCs.

<p>Energy storage devices have become an integral part of the digital infrastructure of the 21st century. Li-ion batteries are a widely used chemical form of energy storage devices comprising components with varied chemical, mechanical and electrochemical properties. Over long-term usage, the anode and cathode experience spatially heterogeneous Li reaction, mechanical degradation, and reversible capacity loss. The small particle size and environmental sensitivity of materials used in Li-ion battery materials make investigating electrodes' electrochemical and mechanical properties an arduous task. Nevertheless, understanding the effect of electrochemical fatigue load (during the battery's charging and discharging process) on composite electrodes' mechanical stability is imperative to design and manufacture long-lasting energy storage devices.</p><p>Due to the low-symmetry lattice, Lithium Nickel Manganese Cobalt Oxide (NMC) cathode materials exhibit direction-dependent (anisotropic) mechanical properties. In this Dissertation, we first measure the anisotropic elastic stiffness of NMC cathode material using nano-indentation. We also determine the effect of Ni stoichiometry on the indentation modulus, hardness, and fracture toughness of NMC materials. The complete information on the mechanical properties of cathode materials will enable accurate computational results and the design of robust cathodes.</p><p>Further, using operando optical experiments, we report that NMC porous composite cathode experiences asynchronous reactions only during the 1st charging process. Non-uniform carbon binder network coverage across the cathode and Li concentration-dependent material properties of NMC results in the initial asynchronous phenomenon. The information on the degree of electrochemical conditioning of Li-ion battery cathode obtained from optical microscopy can test the consistency of product quality in the industrial manufacturing process. We also investigate the effects of non-uniform reactions on active material’s local morphology change and study the evolution of particle network over long-term cycling. Reported data from experiments depicts that in the early cycles, individual particles’ characteristics significantly influence the degree of damage across the cathode.</p><p>However, the interaction with neighboring particles becomes more influential in later cycles. Computational modeling uses a multiphysics-based theoretical framework to explain the interplay between electrochemical activity and mechanical damage. The methodology, theoretical framework, and experimental procedure detailed here will enable the design of efficient composite electrodes for long-lasting batteries.</p>