Professor Liu Ming's team from the National Key Laboratory of Precision Micro-Nano Manufacturing Technology and the School of Electronic Science and Engineering at Xi'an Jiaotong University (XJTU) has proposed a multi-coupling optimization strategy that enhances the output power density of miniaturized magneto-mechano-electric (MME) energy harvesters by strengthening the magneto-mechanical-electrical coupling mechanism.

Based on theoretical research, this strategy constructs a two-degree-of-freedom equivalent spring-mass model and a finite element analysis model to deeply reveal the synergistic mechanism of magneto-mechanical coupling, mechanical coupling, and mechano-electrical coupling.

Based on the above mechanism research, the team achieved a breakthrough in the performance of miniaturized MME energy harvesters by adjusting the relative position of the neutral axis and the bending stiffness of the piezoelectric/elastic phases in the MME energy harvester.

The experimental results show that the strategy achieves a significant 664 percent improvement in the output power density of the MME energy harvester – within a miniature volume of only 0.97 cubic centimeters, the device can generate an output power of up to 0.71 milliwatt under 1 Oe power-frequency weak magnetic field excitation.

Its power density reaches 0.73 mW cm⁻³ Oe⁻², a 124 percent improvement over the best-performing comparable devices to date, demonstrating its unique ability to efficiently capture energy in weak magnetic field environments.

In addition, based on the miniaturized MME energy harvester, the team developed a self-powered wireless sensor network, providing an innovative solution for the sustainable micropower supply of internet of things devices.

The research results, titled Multiple-Coupling Optimization Strategy for Significantly Enhancing the Output Power Density of Compact Magneto-Mechano-Electric Energy Harvester, were published in the top international journal Energy & Environmental Science.