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)
Material design strategies for energy storage applications can be considered in two major categories: (1) control of structure and composition and (2) material dimensional control such as the implementation of nanomaterials. Characterization of electrochemical properties determines energy content and possible viability for potential application. Equally(More)
Silver vanadium oxide (Ag2V4O11, SVO) has enjoyed widespread commercial success over the past 30 years as a cathode material for implantable cardiac defibrillator (ICD) batteries. Recently, silver vanadium phosphorous oxide (Ag2VO2PO4, SVPO) has been studied as possibly combining the desirable thermal stability aspects of LiFePO4 with the electrical(More)
Silver vanadium phosphorous oxides (AgwVxPyOz) are notable battery cathode materials due to their high energy density and demonstrated ability to form in-situ Ag metal nanostructured electrically conductive networks within the cathode. While analogous silver vanadium diphosphate materials have been prepared, electrochemical evaluations of these diphosphate(More)
In situ, in operando characterization of electrochemical cells can provide insight into the complex discharge chemistries of batteries which may not be available with destructive methods. In this study, in situ energy-dispersive X-ray spectroscopy (EDXRD) measurements are conducted for the first time on active lithium/silver vanadium diphosphate,(More)
As a cathode material, silver vanadium phosphorous oxide (Ag(2)VO(2)PO(4)) displays several notable electrochemical properties: large capacity, high current capability, and an effective delivery of high current pulses. These cell performance characteristics can be attributed to the presence of silver nanoparticles formed in-situ during the electrochemical(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)
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)