Kenneth J. Takeuchi

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Battery systems have been developed that provide years of service for implantable medical devices. The primary systems utilize lithium metal anodes with cathode systems including iodine, manganese oxide, carbon monofluoride, silver vanadium oxide and hybrid cathodes. Secondary lithium ion batteries have also been developed for medical applications where the(More)
Batteries are multicomponent systems where the theoretical voltage and stoichiometric electron transfer are defined by the electrochemically active anode and cathode materials. While the electrolyte may not be considered in stoichiometric electron-transfer calculations, it can be a critical factor determining the deliverable energy content of a battery,(More)
The functional capacity of a battery is observed to decrease, often quite dramatically, as discharge rate demands increase. These capacity losses have been attributed to limited ion access and low electrical conductivity, resulting in incomplete electrode use. A strategy to improve electronic conductivity is the design of bimetallic materials that generate(More)
Synthetic control of the silver content in silver hollandite, Ag(x)Mn(8)O(16), where the silver content ranges from 1.0 ≤ x ≤ 1.8 is demonstrated. This level of compositional control was enabled by the development of a lower temperature reflux based synthesis compared to the more commonly reported hydrothermal approach. Notably, the synthetic variance of(More)
Hollandites (OMS-2) are an intriguing class of sorbents, catalysts, and energy storage materials with a tunnel structure permitting one-dimensional insertion and deinsertion of ions and small molecules along the c direction. A 7-fold increase in delivered capacity for Li/AgxMn8O16 electrochemical cells (160 versus 23 mAh/g) observed upon a seemingly small(More)
The combination of ex situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements on 2D layered copper birnessite cathode materials for lithium ion battery applications provides detailed insight into both bulk-crystalline and localized atomic structural changes resulting from electrochemically driven lithium insertion and de-insertion.(More)
When electroactive nanomaterials are fully incorporated into an electrode structure, characterization of the crystallite sizes, agglomerate sizes, and dispersion of the electroactive materials can lend insight into the complex electrochemistry associated with composite electrodes. In this study, composite magnetite electrodes were sectioned using(More)
Magnetite (Fe3O4) is an abundant, low cost, environmentally benign material with potential application in batteries. Recently, low temperature coprecipitation methods have enabled preparation of a series of nanocrystalline magnetite samples with a range of crystallite sizes. Electrochemical cells based on Li/Fe3O4 show a linear increase in capacity with(More)
As a part of our on-going study on silver vanadium phosphorous oxides (Ag(x)V(y)O(z)PO(4)), we report here the first study of the electrochemical reduction of a low Ag/V ratio silver vanadium phosphorous oxide, Ag(0.48)VOPO(4)·1.9H(2)O. Reminiscent of Ag(2)VO(2)PO(4) reduction, in-situ formation of silver metal nanoparticles along with an associated(More)
A paradigm for concomitant control of crystallite size and composition of bimetallic composites via co-precipitation is introduced. Direct preparation of composites of silver ferrite and amorphous maghemite via nonstoichiometric synthesis was demonstrated. Notable impact on electrochemistry was observed, with ∼200% increase in reversible capacity for the(More)