• Energy Research

Illustration of protein-based MEG generating electricity by absorbing water from moisture.

Abstract Metal oxide nanosheets have potential applications in novel nanoelectronics as nanocrystal building blocks. In this work, the devices with a structure of Au/p-type Co3O4 nanosheets/indium tin oxide/glass having bipolar resistive switching characteristics were successfully fabricated. The experimental results demonstrate that the device have stable high/low resistance ratio that is greater than 25, endurance performance more than 200 cycles, and data retention more than 10,000 s. Such a superior performance of the as-fabricated device could be explained by the bulk film and Co3O4/indium tin oxide glass substrate interface effect.

Quasi-solid-state silver-zinc (Ag-Zn) batteries, featuring high energy density, stable voltage output, and outstanding safety, have been considered as promising power source for wearable electronics, while they suffer from poor areal capacity and insufficient rechargeability caused by low surface area and structural deterioration of cathode. In this work, we address these problems through redesigning the cathode with core-shell AgCl/carbon fiber structure decorated with MXene nanosheets. Benefiting from the unique structure with high surface area, the capacity is over two times higher than that with irregular morphology, and undesired Ag migration is suppressed owing to MXene protective layer, leading to enhanced structural integrity and ultralong cycle life. Theoretical calculations and experimental result reveal that a heterostructure is formed between MXene and Zn-coated AgCl, stabilizing the cathode structure. The battery demonstrates high capacity of 2.97 mAh cm−2 and impressive cyclability, maintaining 78% of initial capacity after 400 cycles at 4 mA cm−2, with nearly 100% coulombic efficiency. Moreover, robust mechanical flexibility is demonstrated in the separator-free batteries, and they can operate when twisted, cut, put on fire, and sealed in ice, suggesting the viability for practical application scenarios. This work offers pivotal guidance to construct stable electrodes and advanced batteries for powering electronics.

Abstract Conversion and utilization of solar energy is one of the most important strategies being proposed to mitigate the foreshadowed global energy crisis and environmental issues. Amongst the various solar energy conversion pathways, solar-thermal energy conversion is the most straightforward and efficient. Photothermal materials form the key platform for efficient light-to-heat conversion. The generated heat can be utilized to drive steam generation, which has recently attracted widespread and intense research interests due to its great potential to be a cost-effective and environmentally friendly technique for clean-water production. In recent years, extensive efforts have been devoted to improving the efficiency of solar steam generation. The exploration of photothermal materials with extremely high light-to-heat conversion efficiency as well as innovative evaporation configurations paved the way for eminent practical applications. In this article, the photothermal effect of different categories of light absorbing materials is reviewed and discussed. The applications of a series of representative photothermal materials for solar-steam generation are introduced and summarized in detail to reflect the state-of-the-art for solar evaporation. Finally, a brief discussion of the future research perspectives in this field are proposed.

Abstract Ti-doped ZnO (ZnO/Ti) thin films were grown on indium tin oxide substrates by a facile electrodeposition route. The morphology, crystal structure and resistive switching properties were examined, respectively. The morphology reveals that grains are composed of small crystals. The (002) preferential growth along c-axis of ZnO/Ti could be observed from structural analysis. The XPS study shows the presence of oxygen vacancies in the prepared films. Typical bipolar and reversible resistance switching effects were observed. High R OFF/R ON ratios (approximately 14) and low operation voltages within 100 switching cycles are obtained. The filament theory and the interface effect are suggested to be responsible for the resistive switching phenomenon.

AbstractDirect conversion of low‐grade heat into electricity by thermal electrochemical cells is a promising strategy for energy generation. For stable heat‐to‐electricity conversion, maintaining a low‐grade heat induced temperature difference between the cell electrodes is essential. Here, a thermogalvanic cell consisting of a cellulose fiber‐based porous aerogel, a liquid electrolyte, a reduced graphene oxide light absorber, and carbon nanotube‐based electrodes is designed for low‐grade thermal energy harvesting and conversion. The low thermal conductivity of the porous cellulose aerogel enables limited heat transfer from the hot side to the cold side, and thermal energy management effectively reduces heat loss from the hot side to the environment. Thus, a sustainable temperature difference between the electrodes is maintained and a corresponding maximum power output of 6.94 mW m−2 is achieved under natural solar irradiation. The obtained thermal electrochemical cells are also integrated into an enclosed interfacial solar evaporation device to harvest the latent heat released from vapor condensation for electricity generation. In addition, the thermal electrochemical cells can be regenerated after 18 months of storage and show no performance degradation. This design thus offers a novel alternative strategy for practical low‐grade heat harvesting.image

Refereed/Peer-reviewed As an emerging candidate for a sustainable power supply, moisture-electric generators (MEGs) have attracted great attention in recent years. Unlike the conventional hydroelectric system, MEGs propose to harvest energy from ambient moisture, driven by either ion diffusion under a concentration gradient or the interaction between a solid-liquid interface governed by electrostatic theory. Two-dimensional (2D) nanomaterials, in particular hydrophilic graphene oxide (GO), have been considered as the most promising materials for high-performance MEGs owing to their unique structure and properties. In line with the development of 2D nanomaterials, the recent electrical output of a single MEG has been greatly raised from tens to hundreds of millivolts, which is capable of powering commercial electronics. Herein, we have reviewed the recent progress of 2D nanomaterials in MEGs. The mechanism of moisture-induced electricity generation and strategies for tailoring 2D nanomaterials to enhance the output performance of MEGs are discussed. The potential application of MEGs is also discussed in two categories: sensing and power supply. Finally, the existing challenges and the perspective of MEGs are proposed for future study.