Abstract Hydrovoltaic technology is a promising approach for clean and renewable energy generation, owing to its unique ability to generate electricity from the interactions between nanomaterials and abundant water. However, the output current of hydroelectric generators needs improvement, which is usually below 1 mA. Here, we demonstrate a large-scale integration of water-graphite hydroelectric generators that can produce an output current of up to 58 mA, surpassing the performance of existing hydroelectric generators, and capable of powering commercial electronics, such as electric fans and full-color liquid crystal display screens. The high current is achieved by utilizing the asymmetric electric double layer formed at the water-graphite interface when immersed in water. Our results show that this low-cost and scalable hydroelectric generator has the potential to significantly expand the application domain and facilitate the development of clean and renewable energy sources.
Two-dimensional materials have potential applications for flexible thermoelectric materials because of their excellent mechanical and unique electronic transport properties. Here we present a functionalization method by a Lewis acid-base reaction to modulate atomic structure and electronic properties at surface of the MoS2nanosheets. By AlCl3solution doping, the lone pair electronics from S atoms would enter into the empty orbitals of Al3+ions, which made the Fermi level of the 1T phase MoS2move towards valence band, achieving a 1.8-fold enhancement of the thermoelectric power factor. Meanwhile, benefiting from the chemical welding effect of Al3+ions, the mechanical flexibility of the nanosheets restacking has been improved. We fabricate a wearable thermoelectric wristband based on this improved MoS2nanosheets and achieved 5 mV voltage output when contacting with human body. We think this method makes most of the transition metal chalcogenides have great potential to harvest human body heat for supplying wearable electronic devices due to their similar molecular structure.
Solution-based processing of two-dimensional (2D) materials provides the possibility of allowing these materials to be incorporated into large-area thin films, which can translate the interesting fundamental properties of 2D materials into available devices. Here, we report for the first time a novel chemical-welding method to achieve high-performance flexible n-type thermoelectric films using 2D semimetallic TiS2 nanosheets. We employ chemically exfoliated TiS2 nanosheets bridged with multivalent cationic metal Al3+ to cross-link the nearby sheets during the film deposition process. We find that such a treatment can greatly enhance the stability of the film and can improve the power factor by simultaneously increasing the Seebeck coefficient and electrical conductivity. The resulting TiS2 nanosheet-based flexible film shows a room temperature power factor of ∼216.7 μW m-1 K-2, which is among the highest chemically exfoliated 2D transition-metal dichalcogenide nanosheet-based films and comparable to the best flexible n-type thermoelectric films, to our knowledge, indicating its potential applications in wearable electronics.
The development of high performance flexible thermoelectric materials is important for fabricating wearable thermoelectric generators that can directly convert waste body heat into electricity. In this work, flexible thermoelectric thin films based on elemental tellurium have been fabricated via electrodeposition followed by a transfer process using adhesive substrates, which show not only high flexibility but also a large power factor of 3.21 μW cm−1 K−2 at room temperature. The flexible thermoelectric thin films can be activated by the heat of fingertips, and a large output voltage of 15 mV can be generated thanks to the large room temperature Seebeck coefficient of the films. It is anticipated that this work may pave the way for fabricating low cost and high performance flexible thermoelectric thin films.
Recent years have witnessed substantial advancements in wearable thermoelectric generators (TEGs) leveraging 2D thin-film structures. However, the rational design of TEGs that harmonizes high output performance, stretchability, and comfort remains a challenge. Herein, p-type and n-type thermoelectric units are alternately arranged on a flexible tellurium (Te) film using a solvothermal method combined with an in situ reaction. This methodology facilitates the fabrication of a wearable wavy structure TEG with an impressive stretchability of up to 300%. The effect of the geometric parameters of the wavy structure on TEG performance is explored. The designed TEG with three p–n pairs (TEG-3pn) achieves an open-circuit voltage output of 50.46 mV at a temperature difference of 60 K. Demonstrations of thermal energy harvesting from the human wrist and a hot water cup underscored the TEG's efficient exploitation of vertical temperature gradients and its versatility for diverse applications. This work provides a straightforward and practical strategy for designing thin-film-based 3D TEGs, addressing both structural considerations and the impact of geometric parameters on performance.
Hydroelectricity is an emerging novel electricity generation phenomenon that can generate electric power simply when nanostructured materials are in direct contact with omnipresent liquid water or moisture. In this work, after alkali treatment, a molybdenum disulfide (MoS2) sponge can produce a high-output voltage of about 430 mV and a remarkable output current of 62 μA under a relative humidity of 80%, which is over three times and 20 times as compared with that of pure MoS2 coating sponges, respectively, and it also achieves a continuous electric output over 1 h with good stability. The increasing number of movable cations after alkali treatment probably results in the improvement of power generation performance. Demonstrating the ability of the MoS2 coating sponges to function as a practical power source, the output voltage of the devices is further scaled up to 10 V by simple series connections, and capacitors charged to 5 V are able to power an electronic screen with single-chip computers.
Hydrovoltaic technology is a promising approach for clean and renewable energy generation, owing to its unique ability to generate electricity from the interactions between nanomaterials and abundant water.
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