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Wearable exoskeletons are developing rapidly due to their superiority in improving human ability and efficiency. The construction of a multifunctional exoskeleton system relies on an efficient continuous energy supply and various high-performance sensors. Here, a magnetic-driven piezoelectric cantilever generator (MPCG) array is designed for energy harvesting and angle sensing of joint motions. Combining theoretical derivation and experimental characterization, it is found that the nonlinear magnetic force acting on the cantilever structure will cause the phenomenon of frequency upconversion, which greatly improves the output of the MPCG. The experiment successfully proves the feasibility of using the MPCG array as an energy-harvesting module to collect energy from human joint motions and power an RH/temp sensor. Furthermore, the MPCG array can also be used to sense the rotation angle and angular velocity. By integrating with a wireless data acquisition and transmission module and supporting software, a wearable joint rehabilitation monitoring and assessment system is built, which can measure the activities of the joint in real time and evaluate the flexion degree. The demonstrated wearable exoskeleton system for joint motion energy harvesting and joint angle sensing is of great value for the construction of a multifunctional exoskeleton system and wearable smart rehabilitation equipment.

Tactile perception includes the direct response of tactile corpuscles to environmental stimuli and psychological parameters associated with brain recognition. To date, several artificial haptic-based sensing techniques can accurately measure physical stimuli. However, quantifying the psychological parameters of tactile perception to achieve texture and roughness identification remains challenging. Here, we developed a smart finger with surpassed human tactile perception, which enabled accurate identification of material type and roughness through the integration of triboelectric sensing and machine learning. In principle, as each material has different capabilities to gain or lose electrons, a unique triboelectric fingerprint output will be generated when the triboelectric sensor is in contact with the measured object. The construction of a triboelectric sensor array could further eliminate interference from the environment, and the accuracy rate of material identification was as high as 96.8%. The proposed smart finger provides the possibility to impart artificial tactile perception to manipulators or prosthetics.

Assessment of muscle function is an essential indicator for estimating elderly health, evaluating motor function, and instructing rehabilitation training, which also sets urgent requirements for mechanical sensors with superior quantification, accuracy, and reliability. To overcome the rigidity and vulnerability of traditional metallic electrodes, we synthesize an ionic hydrogel with large deformation tolerance and fast self-healing ability. And we propose a stretchable, self-healing, and skin-mounted (Triple S) active sensor (TSAS) based on the principles of electrostatic induction and electrostatic coupling. The skin modulus-matched TSAS provides outstanding sensing properties: maximum output voltage of 78.44 V, minimal detection limit of 0.2 mN, fast response time of 1.03 ms, high signal-to-noise ratio and excellent long-term service stability. In training of arm muscle, the functional signals of biceps and triceps brachii muscles as well as the joint dexterity of bending angle can be acquired simultaneously through TSAS. The signal can also be sent wirelessly to a terminal for analysis. With the characteristics of high sensitivity, reliability, convenience, and low-cost, TSAS shows its potential to be the next-generation procedure for real-time assessment of muscle function and rehabilitation training.

Self‐powerability is a new trend in the development of portable devices. Harvesting biomechanical energy to power personal information electronics is of great significance. In this work, we report a wearable noncontact free‐rotating hybrid nanogenerator (WRG), which is constituted by a triboelectric nanogenerator and an electromagnetic generator. A continuous output over 2 seconds can be achieved during one instantaneous incentive by external force, which is improved by two orders of magnitude compared to other wearable nanogenerators due to its unique mechanical energy storage design. The WRG can be integrated into shoes to generate an output energy of 14.68 mJ in each stepping, which meets the power requirements of most personal information electronics. The wireless sensor, GPS, and smartphone can be powered by the WRG continuously. The WRG is expected to be applied in self‐powered information electronics extensively in the future.

Virtual reality is a brand-new technology that can be applied extensively. To realize virtual reality, certain types of human-computer interaction equipment are necessary. Existing virtual reality technologies often rely on cameras, data gloves, game pads, and other equipment. These equipment are either bulky, inconvenient to carry and use, or expensive to popularize. Therefore, the development of a convenient and low-cost high-precision human-computer interaction device can contribute positively to the development of virtual reality technology. In this study, a gesture recognition wristband that can realize a full keyboard and multicommand input is developed. The wristband is convenient to wear, low in cost, and does not affect other daily operations of the hand. This wristband is based on physiological anatomy as well as aided by active sensor and machine learning technology; it can achieve a maximum accuracy of 92.6% in recognizing 26 letters. This wristband offers broad application prospects in the fields of gesture command recognition, assistive devices for the disabled, and wearable electronics.

Elastic and electrical conductive sponges are attracting materials for energy storage and energy harvest devices. In this study, we have demonstrated that a flexible and durable Cu doped PDMS sponge (Cu) can be adopted as electrodes for triboelectric nanogenerators (TENG) and flexible supercapacitors (SC). The Cu sponge loading with polypyrrole (PPy) was newly applied as single-electrode TENG for the first time. The outputs of the TENG were tuned by varying the PPy content or by combining with PDMS sponge. Due to the feasibility of changing the PPy content in the Cu@PPy sponges, this study offers a facile way to enhance the performance of TENG from the material itself with a tunable manner. Moreover, this study potentiates a better understanding of the triboelectricity produced by the TENG from the view of materials. The Cu@PPy sponges were further utilized as electrodes for all solid-state symmetrical SCs, in which the Cu sponge and PPy showed a synergistic effect on promoting the stability and performance of the SC. The SC exhibits lightweight, good capacitance, high flexibility, excellent mechanical and long-term stability, which is suitable for wearable energy storage devices. For the application of the TENG and the SC, a self-powered hybrid device was assembled, which provides a prospect for integrated devices. As a summary, we reported a new metal sponge based TENG and self-powered hybrid device, which demonstrated our study provides new opportunities for elastic multifunctional power sources and potential applications in wearable electronics.

With the advantages of being lightweight, flexible, and wearable, wire-shaped supercapacitors have received tremendous attention in wearable and portable power sources in recent years. Considering the demands for large-scale applications, it is necessary to explore a facile and convenient preparation approach for wire-shaped supercapacitors. Herein, we reported a simple approach to fabricate wire-shaped electrodes by a dipping method, which possessed a nitric acid-activated graphite fiber core and an activated carbon-coating layer structure. Parallel and symmetric all-solid-state wire-shaped supercapacitors (PWSCs) based on the electrodes were fabricated. The as-fabricated PWSC showed high energy density (6.60 W h/kg, 8.08 mW h/cm, and 1 mV/s) and power density (253 mW/kg, 0.31 mW/cm, and 100 mV/s) and excellent flexibility. Furthermore, this wire-shaped supercapacitor may bring broader application prospects for energy storage devices in future wearable electronic areas.

Soft wearable electronics for underwater applications are of interest, but depend on the development of a waterproof, long-term sustainable power source. In this work, we report a bionic stretchable nanogenerator for underwater energy harvesting that mimics the structure of ion channels on the cytomembrane of electrocyte in an electric eel. Combining the effects of triboelectrification caused by flowing liquid and principles of electrostatic induction, the bionic stretchable nanogenerator can harvest mechanical energy from human motion underwater and output an open-circuit voltage over 10 V. Underwater applications of a bionic stretchable nanogenerator have also been demonstrated, such as human body multi-position motion monitoring and an undersea rescue system. The advantages of excellent flexibility, stretchability, outstanding tensile fatigue resistance (over 50,000 times) and underwater performance make the bionic stretchable nanogenerator a promising sustainable power source for the soft wearable electronics used underwater., Flexible devices such as solar cells and nanogenerators are attractive for powering wearable electronics, but waterproof capabilities would extend applications. Here the authors report a bionic stretchable nanogenerator that is capable of harvesting energy and multi-position motion monitoring underwater.

Implantable medical electronic devices are usually powered by batteries or capacitors, which have to be removed from the body after completing their function due to their non‐biodegradable property. Here, a fully bioabsorbable capacitor (BC) is developed for life‐time implantation. The BC has a symmetrical layer‐by‐layer structure, including polylactic acid (PLA) supporting substrate, PLA nanopillar arrays, self‐assembled zinc oxide nanoporous layer, and polyvinyl alcohol/phosphate buffer solution (PVA/PBS) hydrogel. The as‐fabricated BC can not only work normally in air but also in a liquid environment, including PBS and the animal body. Long‐term normal work time is achieved to 30 days in PBS and 50 days in Sprague–Dawley (SD) rats. The work time of BC in the liquid environment is tunable from days to weeks by adopting different encapsulations along BC edges. Capacitance retention of 70% is achieved after 3000 cycles. Three BCs in series can light up 15 green light‐emitting diodes (LEDs) in vivo. Additionally, after completing its mission, the BC can be fully degraded in vivo and reabsorbed by a SD rat. Considering its performance, the developed BC has a great potential as a fully bioabsorbable power source for transient electronics and implantable medical devices.

In the past 10 years, the development of nanogenerators (NG) has enabled different systems to operate without external power supply. NG have the ability to harvest the mechanical energies in different forms. Human body motions and activities can also serve as the energy source to drive NG and enable self-powered healthcare system. In this review, a summary of several major actual applications of NG in the biomedical fields is made including the circulatory system, the neural system, cell modulation, microbe disinfection, and biodegradable electronics. Nevertheless, there are still many challenges for NG to be actually adopted in clinical applications, including the miniaturization, duration, encapsulation, and output performance. It is also very important to further combine the NG development more precisely with the medical principles. In future, NG can serve as highly promising complementary or even alternative power suppliers to traditional batteries for the healthcare electronics.

Transient electronics provide an effective technology to develop bioabsorbable implantable medical devices (IMDs). In article number 1801625, Yubo Fan, Zhong Lin Wang, Zhou Li, and co‐workers design a new fully bioabsorbable capacitor as an energy storage unit for IMDs. This capacitor achieves good working performance and full biodegradability in animals.