Room‐Temperature Fabrication of Lithium Cobalt Oxide Thin‐Film Electrodes by Lithium Hydroxide Solution Treatment

Abstract

An economical, energy-efficient, and environmentally friendly solution process was used to prepare lithiated thinfilm electrodes as a cathode for lithium rechargeable microbatteries. Well-crystallized and electrochemically active lithium cobalt oxide thin-film electrodes were spontaneously fabricated in a single synthetic step in a 4M lithium hydroxide solution at room temperature without any postsynthesis annealing. The estimated film properties show that the obtained spinel lithium cobalt oxide films (space group Fd3m) has possible use as a desired cathode film.

Room-temperature synthesis of crystallized LiCoO2 thin films by electrochemical technique

“…This may be originated from the orientation of the Co substrate. Similar results have been reported in Tao's paper [29] and Han's paper [34]. In her paper, Tao pointed out "About films on cobalt, it indicate that the more of the (0 0 3) reflection for the films, the more of grains are aligned with its (0 0 3) plane parallel to cobalt substrate, i.e., the more grains have those c axes aligned normal to the plane of films."…”

Effect of 20°–200oC Fabrication Temperature on Microstructure of Hydrothermally Prepared LiCoO2 Films

“…[17][18][19] In addition, we have successfully produced an LiCoO 2 film, even at room temperature. 20 We have also found that film properties can be controlled by varying the hydrothermal conditions, such as fabrication temperature and concentration of alkaline solution, as well as the electrochemical reaction conditions, such as current and voltage. Among those reaction factors, the fabrication temperature plays the main role in controlling the film structure of LiCoO 2 , which is one of the most promising positive electrode materials in advanced rechargeable lithium batteries.…”

“…Film preparation was performed in a laboratory-made stainless-steel autoclave, with a Teflon vessel adapted to the pressure vessel (15.0 cm long, with a diameter of 10.0 cm), as described in our previous papers. [17][18][19][20] The temperature profile of the hydrothermal reaction was controlled up to the given reaction temperatures of 80°, 100°, 125°, 150°, 175°, and 200°C, with an approximate heating rate of 1°C/min and subsequent isothermal treatment for 20 h, followed by the cooling process. No external pressure or gas injection were added; thus, the atmosphere was saturated with water vapor during the hydrothermal process.…”

Quantum Confinement Effects of Thin Co3O4 Films

“…In last year's research, cobalt tetraoxide was identified as a future supercapacitor [18] and cathode material for rechargeable lithium-ion batteries. Notably, Co 3 O 4 has a high theoretical capacity of 890 mAh/g [19]. It is one of the most promising anode materials for this type of battery.…”