A Battery‐Like Self‐Charge Universal Module for Motional Energy Harvest

Abstract

DOI: 10.1002/aenm.201901875 Recent years, wearable and portable electronics have experienced tremendous development.[1–3] Nowadays, they are influencing every aspects of our lives and have brought great convenience to us.[4] Most of these electronics are powered by batteries.[5–7] While, the battery has limited lifetime and will eventually run out of electricity. Even if using the rechargeable battery, a power grid is needed, which brings time and space constraints on the use of these widely distributed wearable and portable electronic devices.[8] Therefore, developing a sustainable power source to match up with the wearable and portable devices is of great importance. It will extend the use time of wearable/ portable electronics especially in some extreme situations, such as during the blackouts time or in the wild. Mechanical energy is widely existing in the environment around us, which has been utilized by humans for a long time.[9] For example, the electricity from wave energy,[10,11] wind energy.[12–14] Besides, the movement of human beings and various vehicles motion also contain a large amount of mechanical energy.[15–17] It would be a potential auxiliary for today’s battery technology if these energies can be gathered and converted into electricity. And it will bring new opportunities for developing wearable/portable electronics to overcome some of lifetime related limitations.[18,19] In order to utilize widely distributed, random mechanical energy in environment, many sophisticated design[20] and advanced materials of energy conversion devices have been invented.[21,22] Representatives among them are electromagnetic generator (EMG),[23] piezoelectric nanogenerator (PENG),[24–26] and triboelectric nanogenerator (TENG),[27,28] each of them has its unique characteristics. Generally speaking, with a same mechanical load, TENG exhibits the highest voltage output, while EMG demonstrates a better performance in current output,[29,30] which can form a good complementary in power generation process. On the other hand, TENG and EMG can easily respond to displacement produced by mechanical motion, while PENG is more suitable for responding to strain.[31,32] In consideration of those interesting properties, a hybrid generator can be designed to integrate these three modes of generators. It will improve the power efficiency and the ability to collect various kinds of mechanical energies for an energy conversion device.[33] There have been several researches on hybrid generator for improving output performance (Table S1, Supporting Wearable and portable electronics have brought great convenience. These battery-powered commercial devices have a limited lifetime and require recharging, which makes more extensive applications challenging. Here, a battery-like self-charge universal module (SUM) is developed, which is able to efficiently convert mechanical energy into electrical energy and store it in one device. An integrated SUM consists of a power management unit and an energy harvesting unit. Compared to other mechanical energy harvesting devices, SUM is more ingenious, efficient and can be universally used as a battery. Under low frequency (5 Hz), a SUM can deliver an excellent normalized output power of 2 mW g−1. After carrying several SUMs and jogging for 10 min, a commercial global positioning system module is powered and works continuously for 0.5 h. SUMs can be easily assembled into different packages for powering various commercial electronics, demonstrating the great application prospects of SUM as a sustainable battery-like device for wearable and portable electronics.