This paper describes a totally solid-state, rechargeable, long cycle life lithium-oxygen battery cell. The cell is comprised of a Li metal anode, a highly Li-ion conductive solid electrolyte membrane laminate fabricated from glass-ceramic ͑GC͒ and polymerceramic materials, and a solid-state composite air cathode prepared from high surface area carbon and ionically conducting GC powder. The cell exhibited excellent thermal stability and rechargeability in the 30-105°C temperature range. It was subjected to 40 charge-discharge cycles at current densities ranging from 0.05 to 0.25 mA/cm 2 . The reversible charge/discharge voltage profiles of the Li-O 2 cell with low polarizations between the discharge and charge are remarkable for a displacement-type electrochemical cell reaction involving the reduction of oxygen to form lithium peroxide. The results represent a major contribution in the quest of an ultrahigh energy density electrochemical power source. We believe that the Li-O 2 cell, when fully developed, could exceed specific energies of 1000 Wh/kg in practical configurations.

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In this paper, processing and characterization of sheet, pellet, and membrane specimens based on the lithium aluminum germanium phosphate (LAGP) glass–ceramic system is reported. X-ray diffraction patterns exhibited the presence of normalLi1+xnormalAlxnormalGe2−x(PnormalO4)3 (x=0.5) as the primary phase. Increasing heat-treatment temperature from 850to950°C led to the precipitation of an impurity phase, AlPnormalO4 , and a large increase in LAGP grain size. The highest total conductivity of the LAGP glass–ceramic material (5.08×10−3S∕cm) at 27°C was obtained by crystallizing the glass sheet at 850°C for 12h . The total conductivity of the specimen was in the range of 10−3–10−1S∕cm in the 0–107°C temperature range. The pelletized specimen prepared from the glass–ceramic powder and sintered at 850°C for 9h exhibited a slightly lower conductivity (4.62×10−3S∕cm) at 27°C . The membrane conductivity was above 10−3S∕cm in the 37–107°C temperature range. High grain boundary conductivity is apparent in the LAGP glass-ceramic materials. The impurity phases AlPnormalO4 and normalLi2O were attributed to a characteristic nonlinearity in the Arrhenius plots and mediated the transport of the lithium ion, which is associated with a higher activation energy.

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This paper describes an investigation of the properties of superionic glass–ceramic specimens synthesized from the lithium–aluminum–germanium–phosphate system. The specimens were characterized using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and impedance spectroscopy. The concentration of lithium oxide in the glass–ceramic formulations was the primary variable investigated. It is shown that the ionic conductivity of the specimens was dependent on the lithium oxide concentration. An optimized composition exhibited a conductivity approaching 10−2Scm−1 at around room temperature. The superionic conductivity in these specimens is attributed to the space-charge-mediated effect resulting from the presence of the dielectric Li2O phase. The specimens also displayed different conductivities during heating and cooling scans, referred to in this paper as hysteresis effect.