NIMSAWARD2025-abstracts

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P1-845Visualizing Synthesis Reactions of Cathode Materials for Rechargeable BatteriesKey Words: operando analysis, X-ray absorption spectroscopy, material synthesisExpanding demand for high-performance batteries for EVs and energy storage systemNecessity of developing not only next-generation rechargeable batteries such as all-solid-state batteries but also new innovative battery materialsEfficient material synthesis and efficient optimization of synthesis conditionsIrreversible Ni reduction is confirmed above 700 °C by operando X-ray absorption spectroscopy during LiNiO2synthesis without any side reactions.The irreversible Ni reduction results in an irreversible structural change and should be avoided.ConclusionConcept and Designed FurnaceNi redox during LiNiO2synthesisElucidating the influence of metal-doping on the Ni reduction behaviorComprehensive analysis of differences in reducibility not only for nickel but also for various transition metals in lithium (and sodium) transition oxidesFuture PlanIntroductionUnderstanding synthesis conditions hindering battery performanceFrom trial-and-error synthesis to efficient synthesis with visualized reaction processesIn situ measurement of unknown reaction intermediates (metastable phases) and reaction control throughout the entire synthesis processTheme underDiscussionBattery Materials Analysis Group, GREEN Kei KUBOTAE-mail：： KUBOTA.Kei@nims.go.jp0501001502002502.53.03.54.04.5Capacity / mAh g-1Voltage / V2.53.03.54.04.5Voltage / VNo Li/Ni mixingLiONiPartial Li/Ni mixing>200 mAhg-1Battery performance？<150 mAhg-1LiOH∙H2ONi(OH)2Experimental conditions・Composition・Temperature・Time・Atmosphere etc.Conventional methodRReeppeeaatteeddccoonnssiiddeerraattiioonnssSynthesis processData visualization of the reaction process by in-situ measurementLLiiNNiiOO22EExxaammppllee:: LLiiNNiiOO22ccaatthhooddee mmaatteerriiaallX-rayAu sample holder avoiding side reactions with samplesHigh-temp. electric furnacesetup at Photon Factory, KEK in Tsukuba832583308335834083458350835583600.00.20.40.60.81.01.21.41.61.8Normalized AbsorptionEnergy / eVLiOH·H2O + Ni(OH)2(Li/Ni=1.01)1003005007009008342.08342.58343.08343.58344.08344.58345.08345.58346.0E0 (μ(E) = 1.0) / eVTemperature / °C01002003004005006007008009001.851.901.952.002.052.10Ni-O distance / ÅTemperature / °CNi4+ in Ni1/3Mn2/3O2Ni2+ in NiONi2+ in Ni(OH)2Ni3+ in LaNiO3Ni reductionNi oxidation