Continuous advances in microelectronics and micro/nanoelectromechanical systems enable the use of microsized energy storage devices, namely solid-state thin-film -batteries. Different from the current button batteries, the -battery can directly be integrated on microchips forming a very compact "system on chip" since no liquid electrolyte is used in the -battery. The all-solid-state battery (ASSB) that uses solid-state electrolyte has become a research trend because of its high safety and increased capacity. The solid-state thin-film -battery belongs to the family of ASSB but in a small format. However, a lot of scientific and technical issues and challenges are to be resolved before its real application, including the ionic conductivity of the solid-state electrolyte, the electrical conductivity of the electrode, integration technologies, electrochemical-induced strain, etc. To achieve this goal, understanding the processing of thin films and fundamentals of ion transfer in the solid-state electrolytes and hence in the -batteries becomes utmost important. This review therefore focuses on solid-state ionics and provides inside of ion transportation in the solid state and effects of chemistry on electrochemical behaviors and proposes key technology for processing of the -battery.

No abstract

Using ionic liquids (ILs) as electrolytes in developing electrochemical sensors for SO2 detection is of much interest. We compared the electrochemical behaviors of SO2 in choline chloride–ethylene glycol-based deep eutectic solvent (ChCl–EG-based DES), 1-(3-hydroxypropyl)-3-methylimidazolium tetrafluoroboride ([C3OHmim]BF4), and [C3OHmim][Formula: see text]monoethanolamine (MEA) (6.2:1 in molar ratio). Addition of MEA into [C3OHmim]BF4 can significantly increase the SO2 absorption capacity and enhance the electrochemical response of SO2. However, as we use ChCl–EG-based DES, the reduction current is 10 times larger than in [C3OHmim]BF4 and 4 times larger than in [C3OHmim][Formula: see text]MEA (6.2:1 in molar ratio). And SO2 gas shows high diffusion coefficient value as in the ChCl–EG-based DES. A good linear relationship between the reduction current and the SO2 content was obtained in the tested SO2 gas content range from 200[Formula: see text]ppm to 1500[Formula: see text]ppm. Our findings provide new route for DESs as electrolytes for SO2 sensor designing with high sensitivity.