A Shape‐Adaptive Thin‐Film‐Based Approach for 50% High‐Efficiency Energy Generation Through Micro‐Grating Sliding Electrification

Abstract

Effectively harvesting ambient mechanical energy is the key for realizing self-powered and autonomous electronics, which addresses limitations of batteries and thus has tremendous applications in sensor networks, wireless devices, and wearable/implantable electronics, etc. Here, a thin-film-based micro-grating triboelectric nanogenerator (MG-TENG) is developed for high-efficiency power generation through conversion of mechanical energy. The shape-adaptive MG-TENG relies on sliding electrification between complementary micro-sized arrays of linear grating, which offers a unique and straightforward solution in harnessing energy from relative sliding motion between surfaces. Operating at a sliding velocity of 10 m/s, a MG-TENG of 60 cm(2) in overall area, 0.2 cm(3) in volume and 0.6 g in weight can deliver an average output power of 3 W (power density of 50 mW cm(-2) and 15 W cm(-3)) at an overall conversion efficiency of ∼ 50%, making it a sufficient power supply to regular electronics, such as light bulbs. The scalable and cost-effective MG-TENG is practically applicable in not only harvesting various mechanical motions but also possibly power generation at a large scale.

A Fully Verified Theoretical Analysis of Contact‐Mode Triboelectric Nanogenerators as a Wearable Power Source

“…[ 2,4,7,9,13,[19][20][21][22][23][24][25] So far, the electric power output of TENGs has been improved up to ≈500 W m −2 by sophisticated design of device structure. [ 18,[26][27][28] Demonstrated TENGs have been working in four modes, that is, the contact-separation or contact mode in short, sliding mode, single-electrode mode, and free-standing triboelectric-layer mode. The performance of the TENGs in contact-mode is better than that of TENGs in the sliding mode, because a much higher maximum displacement of TENGs in the sliding mode is required than that of TENGs working in the contact-mode, in order to achieve the same level of open circuit voltage.…”

Triboelectric nanogenerators as flexible power sources

“…The main reason is that the increase of stretch strain can increase circuit-transferred charges. 12 This nanogenerator can effectively scavenge mechanical energy from sliding motions. The TENG has the grating structure, which can improve charge separation cycles.…”

“…[8][9][10][11] Researchers have designed some outstanding TENGs, where the area power density can reach up to 500 W/m 2 and a corresponding conversion total efficiency of about 85%. 12,13 With fast-growing demand for flexible electronics, such as wearable electronics, bendable displays, and electronic skin, flexible TENGs as power sources have been extensively studied. Suitable materials and optimized structures are two key elements, which can affect both the output performance and mechanical stability of the flexible TENGs.…”

Fabric‐Based Integrated Energy Devices for Wearable Activity Monitors

“…air gaps) requires the use of rigid materials, which is clearly incompatible with fl exible devices. A new type of TEG, which is both not reliant on air gaps [ 17 ] and fl exible, [ 18 ] is therefore needed to utilize horizontal friction as an energy source in wearable electronics.To ensure the fully independent operation, the power generated by a TEG also needs to be stored within the wearable system itself, for which an all-solid-state fl exible energy storage device [19][20][21] is needed. Supercapacitors (SCs) appear to be one of the most suitable energy storage devices for this purpose, because they offer a high power density, fast charging/discharging speed, and a long cycle life.…”