Analogous Design of a Microlayered Silicon Oxide‐Based Electrode to the General Electrode Structure for Thin‐Film Lithium‐Ion Batteries

Abstract Development of miniaturized thin‐film lithium‐ion batteries (TF‐LIBs) using vacuum deposition techniques is crucial for low‐scale applications, but addressing low energy density remains a challenge. In this work, structures analogous to SiO_x‐based thin‐film electrodes are designed with close resemblance to traditional LIB slurry formulations including active material, conductive agent, and binder. The thin‐film is produced using mid‐frequency sputtering with a single hybrid target consisting of SiO_x nanoparticles, carbon nanotubes, and polytetrafluoroethylene. The thin‐film SiO_x/PPFC (plasma‐polymerized fluorocarbon) involves a combination of SiO_x and conductive carbon within the PPFC matrix. This results in enhanced electronic conductivity and superior elasticity and hardness in comparison to a conventional pure SiO_x‐based thin‐film. The electrochemical performance of the half‐cell consisting of thin‐film SiO_x/PPFC demonstrates remarkable cycling stability, with a capacity retention of 74.8% up to the 1000th cycle at 0.5 C. In addition, a full cell using the LiNi_0.6Co_0.2Mn_0.2O₂ thin‐film as the cathode material exhibits an exceptional initial capacity of ≈120 mAh g⁻¹ at 0.1 C and cycle performance, marked by a capacity retention of 90.8% from the first cycle to the 500th cycle at a 1 C rate. This work will be a stepping stone for the AM/CB/B composite electrodes in TF‐LIBs.