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In order to reduce the natural frequency of the piezoelectric vibration energy harvester, improve the output power of the piezoelectric vibration energy harvester, and meet the demand of power supply for the low-power wireless switch in the low-frequency vibration environment, an asymmetric hybrid supported beam piezoelectric vibration energy harvester is proposed. The theoretical model of the hybrid support beam was established. The correlation factors affecting the open-circuit voltage and the total output power of the hybrid braced beam were analyzed. The dimensional parameters of the hybrid supported beam piezoelectric energy harvester were optimized by using the optimization method of orthogonal experiments. Different coincidence degrees experiments were used to further optimize the structural design of the hybrid support beam. The test results show that the maximum output power is 770 μW, when the external excitation frequency is 1.0 gand the external resistance is 50 kΩ. Finally, a wireless switch test system was established, and the piezoelectric vibration energy harvester was experimentally verified to be capable of powering the wireless switch.

Ion trapping in electrodes upon long-term cycling is found to be one of the main reasons for performance degradation in electrochromic devices. Galvanostatic and potentiostatic post-treatments can rejuvenate degraded electrochromic layers. However, these procedures require high oxidation potentials, which are neither safe for the electrode-electrolyte system nor compatible with the operation of a full device. In the present paper, we report that degraded electrochromic oxides can be rejuvenated by a photo-electrochemical synergistically induced ion detrapping procedure. The UV light-induced photocurrent assists ion detrapping and limits the applied potential to the safe range used for electrochromic switching. This approach has been demonstrated to be effective for several cathodic electrochromic oxides and can be directly implemented in a full device. Our findings provide new vistas for efforts to expand the lifespan of electrochromic devices and other ion intercalation-based devices.

In order to reduce the natural frequency of the piezoelectric vibration energy harvester, improve performance of the piezoelectric vibration energy harvester, and meet the requirements of energy acquisition in the low-frequency vibration environment, a variable-section circular piezoelectric vibration energy harvester is presented. The dynamic model and electromechanical coupling model of variable-section circular piezoelectric vibration energy harvester are established. The main factors affecting the output performance of piezoelectric vibration energy harvester are analyzed. The structure parameters of piezoelectric vibration energy harvester are optimized by orthogonal experiment. An experimental platform is built to test output voltage and output power of piezoelectric vibration energy harvester. The experimental results show that when the number of energy harvester is 4 and the external load is 180KΩ, the parallel output power can reach 0.213mW, which can meet the requirements of micro-power device power supply.