deal of research has gone into the development of vibration energy harvesters (also known as vibration power generators) over the past decade. Based on the structural architecture, vibration energy harvesters can be categorized as either resonant generators (or inertial force generator) or direct force generators. [4] Instead of harnessing the deformation of a material (e.g., pressing, flexing, or stretching motion) induced by direct forces, a resonant generator typically consists of a rigid casing with a seismic mass suspended inside. [4] To date, most of ambient vibration energy harvesters adopt the resonator design, because it only requires one point of attachment to the vibration source which makes the mounting more convenient. [4] The mass moves relative to the casing in response to external vibration and simultaneously, converts kinetic energy into electricity through electrostatic, electromagnetic, piezoelectric, or triboelectric transduction mechanisms. [5][6][7][8] Despite the considerable research effort on vibration energy harvesters, several challenges still exist, which limit the widespread usage of resonant vibration energy harvesters. For a practically useful resonant generator in the context of wireless sensor nodes, at least four criteria need to be satisfied. (1) The device needs to be highly miniaturized (e.g., footprint <1 cm 2 ) to fit in a typical wireless sensor node. [3] This goal can be achieved by the adoption of microelectromechanical systems (MEMS) technology. [1] (2) A low operating frequency which matches the frequency range of the target vibration sources is needed to obtain maximum efficiency. [9] However, typical resonant generators (such as MEMS energy harvesters) are based on springs made of rigid materials which intrinsically tend to exhibit high resonant frequencies. [10] (3) Broadband response and (4) resonance tunability which can significantly improve the efficiency as most real-world vibrations have widely distributed frequency spectra or time variant frequency peak. [11][12][13] However, typical resonant generators are based on linear resonators which have narrow bandwidth and a single resonant frequency. [11,[14][15][16] Here, we demonstrate a design construct and materials for a soft-rigid hybrid device enabling broadband, resonance tunable vibration energy harvesting and self-powered motion sensing. The key concept of the reported design, which is inspired in part by recent works on soft electronics and soft A miniaturized vibration energy harvester, a small yet sustainable power source that converts ambient mechanical vibration into electricity, is considered as a key technology to advance wireless sensor networks for the internet of things. Conventional chip-scale vibration energy harvesters, such as microelectromechanical systems devices that are mostly based on rigid materials (e.g., silicon), inherently exhibit high resonant frequency, narrow bandwidth, and a single peak frequency. Therefore, they are often unsuitable for many real-life applications, as most ambie...

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