Lithium silicon tin oxynitride (Li ySiTON): high-performance anode in thin-film lithium-ion batteries for microelectronics

• Published in: Journal of power sources 1999-09, Vol.81, p.27-32
• Main Authors: Neudecker, B.J., Zuhr, R.A., Bates, J.B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Heat treatment; Hysteresis; Lithium-ion battery; Microelectronics; Silicon tin oxynitride (SiTON); Solder reflow
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/S0378-7753(98)00202-X

A lithium-ion thin-film battery, consisting of the amorphous silicon tin oxynitride anode (`SiTON'), the amorphous lithium phosphorus oxynitride electrolyte (`Lipon'), and a crystalline LiCoO 2 cathode, can be heated at 250°C in air for 1 h which exceeds by far the required solder reflow conditions for electronic circuit assembly. Moreover, the performance of such a battery was found to even improve after the heat treatment. The Li y SiTON profile between 0 and 1.2 V vs. Li was determined in SiTON/Lipon/LiCoO 2 lithium-ion thin-film cells equipped with a Li metal reference electrode. By comparison with a Sn 3N 4/Lipon/LiCoO 2 three-electrode lithium-ion thin-film cell, a model for the electrochemical insertion/extraction process of Li y SiTON was suggested. The SiTON/Lipon/LiCoO 2 cells sustained 5 mA/cm 2 between 4.2 and 2.7 V while the anode supplied a reversible discharge capacity of about 340 μA h/mg or even 450 μA h/mg after heating at 250°C in air for 1 h. A long-term cycling stability test of a SiTON/Lipon/LiCoO 2 battery between 3.93 and 2.7 V demonstrated that the Li y SiTON capacity faded only by 0.001% per cycle when charging was stopped as soon as the Li y SiTON potential reached 0 V vs. Li. When this cathode-heavy cell was charged to 4.1 V (Li y SiTON at 0 V vs. Li), a significantly higher reversible discharge capacity was obtained over ∼5000 cycles.