Wearable electronics are advancing towards miniaturization and flexibility. However, traditional energy supply methods have largely hindered their development. An effective solution to this problem is to convert human mechanical energy into electricity to power wearable electronic devices. Therefore, it is greatly attractive to design flexible, foldable and even stretchable energy harvesting devices. Herein, we use the electrospinning and kirigami approach to develop a type of highly stretchable kirigami-patterned nanofiber-based triboelectric nanogenerator (K-TENG). Due to its innovative structural design, the K-TENG can achieve a tensile strain of 220%, independent of the tensile properties of the material itself. When a person swings their arms, the K-TENG fixed to the clothing can convert mechanical energy from human movement into electrical energy. The produced electricity can directly drive 50 LED lights and a digital watch, or be stored in a lithium battery to charge the smartwatch and smartphone, respectively. This study employs a new method to fabricate a stretchable triboelectric nanogenerator and demonstrates its promising applications in wearable power technology.

The tremendous efforts made in the research field of solid-state Li-ion batteries have led to considerable advancement of this technology and the first market-ready systems can be expected in the near future. The research community is currently investigating different solid-state electrolyte classes (e.g. oxides, sulfides, halides and polymers) with a focus on further optimizing the synthesis and electrochemical performance. However, so far, the development of sustainable recycling strategies allowing for an efficient backflow of critical elements contained in these batteries into the economic cycle and thus a transition from a linear to a circular economy lags behind. In this contribution, resource aspects with respect to the chemical value of crucial materials, which are used for the synthesis of solid-state electrolytes are being discussed. Furthermore, an overview of possible approaches in relation to their challenges and opportunities for the recycling of solid-state batteries with respect to different solid-state electrolyte classes by means of pyrometallurgy, hydrometallurgy and direct recycling/dissolution-based separation processes is given. Based on these considerations and with reference to previous research, it will be shown that different solid-state electrolytes will require individually adapted recycling processes to be suitably designed for a circular economy and that further improvements and investigations will be required.

In recent years, zinc-ion batteries (ZIBs) have been considered one of the most promising candidates for next-generation electrochemical energy storage systems due to their advantages of high safety, high specific capacity and high economic efficiency. As an indispensable component, the electrolyte has the function of connecting the cathode and the anode, and plays a key role in the performance of the battery. Different types of electrolytes have different effects on the performance of ZIBs, and the use of additives has further developed the research on modified electrolytes, thus effectively solving many serious problems faced by ZIBs. Therefore, to further explore the improvement of ZIBs by electrolyte engineering, it is necessary to summarize the current status of the design of various electrolyte additives, as well as their functions and mechanism in ZIBs. This paper analyzes the challenges faced by different electrolytes, reviews the different solutions of additives to solve battery problems in liquid electrolytes and solid electrolytes, and finally makes suggestions for the development of modified ZIB electrolytes. It is hoped that the review and strategies proposed in this paper will facilitate development of new electrolyte additives for ZIBs.

Owing to the capability of the conversion between thermal energy and electrical energy and their advantages of light weight, compactness, noise-free operation, and precision reliability, wearable thermoelectrics show great potential for diverse applications. Among them, weavable thermoelectrics, a subclass with inherent flexibility, wearability, and operability, find utility in harnessing waste heat from irregular heat sources. Given the rapid advancements in this field, a timely review is essential to consolidate the progress and challenge. Here, we provide an overview of the state of weavable thermoelectric materials and devices in wearable smart textiles, encompassing mechanisms, materials, fabrications, device structures, and applications from recent advancements, challenges, and prospects. This review can serve as a valuable reference for researchers in the field of flexible wearable thermoelectric materials and devices and their applications.

Conversion/alloying materials (CAMs) represent a potential alternative to graphite as a Li-ion anode active material, especially for high-power applications. So far, however, essentially all studies on CAMs have been dealing with nano-sized particles, leaving the question of how the performance (and the de-/lithiation mechanism in general) is affected by the particle size. Herein, we comparatively investigate four different samples of Zn_0.9Co_0.1O with a particle size ranging from about 30 nm to a few micrometers. The results show that electrodes made of larger particles are more susceptible to fading due to particle displacement and particle cracking. The results also show that the conversion-type reaction in particular is affected by an increasing particle size, becoming less reversible due to the formation of relatively large transition metal (TM) and alloying metal nanograins upon lithiation, thus hindering an efficient electron transport within the initial particle, while the alloying contribution remains essentially unaffected. The generality of these findings is confirmed by also investigating Sn_0.9Fe_0.1O₂ as a second CAM with a substantially greater contribution of the alloying reaction and employing Fe instead of Co as a TM dopant.

Proton exchange membrane (PEM) water electrolysis represents a promising technology for green hydrogen production, but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts, especially iridium (Ir) based materials for the energy-demanding oxygen evolution reaction (OER). Herein, we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel (Ni) oxy-hydroxide supported on antimony-doped tin oxide (ATO) nanoparticles (IrNi_yO_x/ATO, 20 wt.% (Ir + Ni), y = 0, 1, 2, and 3), aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance. When tested in strongly acidic electrolyte (0.1 M HClO₄), the optimised IrNi₁O_x/ATO shows a mass activity of 1.0 mA µg_Ir⁻¹ and a large turnover frequency of 123 s⁻¹ at an overpotential of 350 mV, as well as a comparatively small Tafel slope of 50 mV dec⁻¹, better than the IrO_x/ATO control, particularly with a markedly reduced Ir loading of only 19.7 µg_Ir cm⁻². Importantly, IrNi₁O_x/ATO also exhibits substantially better catalytic stability than other reference catalysts, able to continuously catalyse acidic OER at 10 mA cm⁻² for 15 h without obvious degradation. Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir³⁺/Ir⁴⁺ species are the active sites for the acidic OER. Furthermore, the performance of IrNi₁O_x/ATO was also preliminarily evaluated in a membrane electrode assembly, which shows better activity and stability than other reference catalysts. The IrNi₁O_x/ATO reported in this work is a promising alternative to commercial IrO₂ based catalysts for PEM electrolysis.

Single crystal is the most advantageous of the crystalline states of halide perovskites. It displays better optical and electrical capabilities than polycrystalline films and microcrystals due to their inherent structural advantages, such as free grain boundaries, long-range ordered structure, and high orientation. Single-crystal perovskite materials can theoretically enable optoelectronic devices with higher performance and stronger stability. In this review, the intrinsic physical properties of perovskite single crystals are analyzed. The most recent advances in single-crystal optoelectronic devices are reviewed, and the design principles of the devices under different application conditions are revealed. It provides potential solutions for remaining challenges, and it is expected to accelerate the development of perovskite based optoelectronic devices.