RESUMO
Replacing the liquid electrolyte in conventional lithium-ion batteries with thin-film solid-state lithium-ion conductors is a promising approach for increasing energy density, lifetime, and safety. In particular, Li7La3Zr2O12 is appealing due to its high lithium-ion conductivity and wide electrochemical stability window. Further insights into thin-film processing of this material are required for its successful integration into solid-state batteries. In this work, we investigate the phase evolution of Li7-3 xGa xLa3Zr2O12 in thin films with various amounts of Li and Ga for stabilizing the cubic phase. Through this work, we gain valuable insights into the crystallization processes unique to thin films and are able to form dense Li7-3 xGa xLa3Zr2O12 layers stabilized in the cubic phase with high in-plane lithium-ion conductivities of up to 1.6 × 10-5 S cm-1 at 30 °C. We also note the formation of cubic Li7La3Zr2O12 at the relatively low temperature of 500 °C.
RESUMO
Active electronic implants are powered by primary batteries, which induces the necessity of implant replacement after battery depletion. This causes repeated interventions in a patients' life, which bears the risk of complications and is costly. By using energy harvesting devices to power the implant, device replacements may be avoided and the device size may be reduced dramatically. Recently, several groups presented prototypes of implants powered by subcutaneous solar cells. However, data about the expected real-life power output of subcutaneously implanted solar cells was lacking so far. In this study, we report the first real-life validation data of energy harvesting by subcutaneous solar cells. Portable light measurement devices that feature solar cells (cell area = 3.6 cm2) and continuously measure a subcutaneous solar cell's output power were built. The measurement devices were worn by volunteers in their daily routine in summer, autumn and winter. In addition to the measured output power, influences such as season, weather and human activity were analyzed. The obtained mean power over the whole study period was 67 µW (=19 µW cm-2), which is sufficient to power e.g. a cardiac pacemaker.
