Fabrication and Characterization of an All-Solid State thin film Microbattery using Rapid Thermal Annealed LiNi_(1-x)Co_xO_2 Cathode Films

摘要

We report on fabrication of all solid-state thin film microbattery(TFB) that has a structure of Li/LiPON/LiNi_(1-x)Co_xO_2/Pt/MgO/Si multilayer. The LiNi_(1-x)Co_xO_2 films were grown by radio-frequency(rf) magnetron reactive sputtering system using synthesized LiNi_(1-x)Co_xO_2 target in a 9:1 Ar/O_2 mixture gas. X-ray diffraction(XRD), transmission electron microscopy(TEM), and selective area diffraction(SAD) analysis show that rapid thermal annealed LiNi_(1-x)Co_xO_2 film has (101) and (104) preferred orientation with increasing film thickness. In addition, scanning electron microscopy(SEM), atomic force microscope(AFM), and Auger electron spectroscopy(AES) examination exhibit that the surface layer on as-deposited LiNi_(1-x)Co_xO_2 film was completely removed by rapid thermal annealing process. All solid state TFB, fabricated by using the annealed LiNi_(1-x)Co_xO_2 cathode film, shows stable cyclibility and high specific discharge capacity of 60.2 mu Ah/cm~2-mum. It was thought that the combined feature of a LiCoO_2 and a LiNiO_2 cathode caused fairly high capacity and stable cyclibility of the LiNi_(1-x)Co_xO_2 based TFB.