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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