Portable and wearable sensors have attracted considerable attention in the healthcare field because they can be worn or implanted into a human body to monitor environmental information. However, sensors cannot work independently and require power. Flexible in-plane micro-supercapacitor (MSC) is a suitable power device that can be integrated with sensors on a single chip. Meanwhile, paper is an ideal flexible substrate because it is cheap and disposable and has a porous and rough surface that enhances interface adhesion with electronic devices. In this study, a new strategy to integrate MSCs, which have excellent electrochemical and mechanical performances, with sensors on a single piece of paper is proposed. The integration is achieved by printing Ni circuit on paper without using a precoating underlay. Ink diffusion is also addressed to some degree. Meanwhile, a UV sensor is integrated on a single paper, and the as-integrated device shows good sensing and self-powering capabilities. MSCs can also be integrated with a gas sensor on one-piece paper and can be charged by connecting it to a solar cell. Thus, it is potentially feasible that a flexible paper can be used for integrating MSCs with solar cell and various sensors to generate, store, and use energy.

The low-temperature magnetic and transport properties of La2/3Sr1/3MnO3 nanoparticles have been investigated. It is found that a surface spin-glass behavior exists in La2/3Sr1/3MnO3 nanoparticles, which undergo a magnetic transition to a frozen state below 45 K. The low-temperature surface spin-glass behavior exists even at the highest field used (H=50 kOe). Moreover, the spin-glass-like transition disappears for particles above 50 nm. In addition, the suppressed low-field magnetoconductivity (LFMC) observed at low temperature for nanosized La2/3Sr1/3MnO3 is obviously lower than the expected upper limit of LFMC, 1/3, for polycrystalline manganites, which is proposed to arise from the higher-order tunneling through the insulating spin-glass-like surface layers.

shopping, detecting body-health, and so on. Nowadays, many major companies are working on exploring more functions on smart watches. In view of diverse functions of smart watches, there are increasing demands on their corresponding energy storage devices with high energy and/or power supply ability. [9][10][11][12][13] However, the energy storage devices are commonly placed in the watches with very small volume, which seriously limit their current energy storage ability and the future boost space. As we know, watchband is an important part of a watch and it plays the fixation function of the watch with a human wrist. Therefore, it can be imagined that, if the watchband had energy storage function, it might meet energy and/or power demands for the smart watches. Taking this into account, such smart watchband should have the right characteristics of flexible energy storage devices, including outstanding electrochemical performance, excellent flexibility, and good performance reliability while bending. In addition, good biocompatibility is a requirement for its practical application because of its direct touch with human skin.Supercapacitors are important energy storage devices, and they have attracted great attention for wearable electronic equipment due to their high power delivery ability, long cycle life, good safety as well as simple manufacturing. [14][15][16][17][18][19][20][21] Here, we demonstrate a new design and fabrication of flexible asymmetric supercapacitors with a smart "watchband-like" function, using reduced graphene oxide (rGO) coated on TiNi alloy (TNA) flake as the negative electrode, MnO 2 deposited on ultrathin Ni foil as the positive electrode, and aqueous or ion liquid-based gel electrolyte as the separator. TNA is a shape memory alloy (SMA) which can "remember" a presupposed shape at high temperature and it is free to bend and can hold the corresponding bending-shape below its phase transition temperature (PTT), and it can restore to the presupposed shape when the temperature is higher than its PTT. [22][23][24][25] In our study, as-made supercapacitors are able to possess excellent electrochemical capacitive properties, maintain the inherent characteristics of SMA (flexibility and shape recovery ability), and have outstanding electrochemical performance reliability while bending. Interestingly, because the PTT of TNA we used is 15 °C, the human skin temperature can directly actuate the shape recovery of the devices. Specifically, we use such a shape Smart watches have gained worldwide popularity because they can integrate diverse functions all in one. However, their energy storage devices currently being used are placed in the watches, and this design seriously limited the energy support ability and the future boost space. Herein, for the first time, a strategy to integrate energy storage device with watchband is put forward, which is realized by the preparation of watchband-like solid-state supercapacitors using graphene coated on TiNi alloy flake as the negative electrode, ultrathin MnO ...

All-solid-state microsupercapacitors (MSCs) have been receiving intense interest due to their potential as micro/nanoscale energy storage devices, but their low energy density has limited practical applications. It has been reported that gel electrolytes based on ionic liquids (ionogels) with large potential windows can be used as solid electrolytes to enhance the energy density of MSCs, but a systematic study on how to select and evaluate such ionogels for MSCs is rare. In this study, we construct a series of all-solid-state asymmetric MSCs on the interdigital finger electrodes, using graphene quantum dots (GQDs) as the negative electrode, MnO2 nanosheets as the positive electrode, and different ionogels as the solid electrolytes. Among them, the MSC using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTF2]) with 4 wt % fumed SiO2 ionogel exhibited the best electrochemical performance, having excellent rate capability with the scan rate up to 2000 V s(-1), ultrafast frequency response (τ0 = 206.9 μs) and high energy density. The outstanding performance of this device mainly results from fast ion diffusion, high ion conductivity of the ionogel, and ionic liquid-matrix interactions. The results presented here provide guidance for picking out appropriate ionogels for use in high-performance all-solid-state MSCs to meet the growing requirement of micronanoscale energy storage devices. Additionally, the ultrafast frequency response of our MSCs suggests potential applications in ac line-filters.