We describe a ZnBr2 single cell which has a highly modular symmetrical structure. With designed polyethylene shell frames, membrane frame and composite titanium-carbon felt electrodes, it has a higher energy density and is more flexible compared with traditional flow batteries. We repeatedly tested its performance, which showed good tightness, high reliability and a high energy efficiency of 75%. Due to the special symmetrical structure and modular design, it is easy to assemble and disassemble, which makes it suitable as a test platform for electrodes, membranes and electrolyte performance testing. The designed modular flow cell has low cost and high energy density, and can provide good guidance for flow battery research.

We describe a novel stable piezoelectric nanopositioner which just use one piezoelectric stack and one simple driving signal, in which the central shaft is clamped by one BeCu spring and four SiN balls that bonded to the inner wall of the cylindrical tube. The cylindrical tube is fixed on the free end of the piezoelectric stack. Applying one increasing voltage signal on the piezoelectric stack, according to the principle of piezoelectricity, the piezoelectric stack will extend smoothly. When canceling this voltage signal suddenly, the piezoelectric will recover to its original length while the central shaft will keep stationary for its inertance. So, the central shaft will be sliding a small distance relative to the piezoelectric stack. Normally, the heavier of the central shaft, the better moving stability, resulting in a high output force of the nanopositioner. Because of the simple structure, simple working principle and good mechanical stability, our novel nanopositioner can be easily used in Scanning Probe Microscopy system and Active Optical mirror adjustment system in large scale astronomical telescope.