Garnet-type Li_(6.4)La_3Zr_(1.4)Ta_(0.6)O_(12) thin sheet: Fabrication and application in lithium-hydrogen peroxide semi-fuel cell

摘要

An Al_2O_3-doped Li_(6.4)La_3Zr_(1.4)Ta_(0.6)O_(12) (LLZTO) cylinder with a cubic garnet structure was prepared by solid state reaction and pressureless sintering. The LLZTO cylinder showed a high relative density of ~94%. LLZTO sheets (200 μm in thickness) were obtained by slicing the LLZTO cylinder using a low speed diamond saw. Ionic conductivity of the sheet was as high as 1.02 × 10~(?3) S·cm~(?1) at room temperature. Two specially designed Li-H_2O_2 semi-fuel cells were assembled using the LLZTO sheet and LTAP sheet (from Ohara, Japan), respectively. The semi-fuel cell employing the LLZTO sheet showed a lower internal resistance and a much higher maximum power density. It discharged at a constant current of 1.0 mA for 1500 min (two "mechanical recharge-discharge" cycles), and relative flat discharge voltage plateaus of ~2.5 V were observed, with an average lithium metal utilization in the cell of 82.0%. The LLZTO thin sheets showed that high quality and could improve the performance of the Li-H_2O_2 semi-fuel cell.