Manganese dioxide (α-MnO2) thin films have been explored as a cathode material for reliable glass capacitors. Conducting α-MnO 2 thin films were deposited on a borosilicate glass substrate by a chemical solution deposition technique. High carbon activities originated from manganese acetate precursor, (Mn(C2H3O2) 2·4H2O) and acetic acid solvent (C 2H4O2), which substantially reduced MnO 2 phase stability, and resulted in Mn2O3 formation at pyrolysis temperature in air. The α-MnO2 structure was stabilized by Ba2+ insertion into a (2 × 2) oxygen tunnel frame to form a hollandite structure. With 15-20 mol% Ba addition, a conducting α-MnO2 thin film was obtained after annealing at 600-650°C, exhibiting low electrical resistivity (∼1 Ω·cm), which enables application as a cathode material for capacitors. The hollandite α-MnO2 phase was stable at 850°C, and thermally reduced to the insulating bixbyte (Mn2O3) phase after annealing at 900°C. The phase transition temperature of Ba containing α-MnO 2 was substantially higher than the reported transition temperature for pure MnO2 (∼500°C).
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry