In recent years, nanocomposites based on various nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a realistic alternative to conventional smart materials, largely due to their superior electrical properties. Great interest has been generated in building highly sensitive strain sensors with these new nanocomposites. This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites. We focus on the following two topics: electrical conductivity and piezoresistivity of CNT/polymer nanocomposites, and the relationship between them by considering the internal conductive network formed by CNTs, tunneling effect, aspect ratio and piezoresistivity of CNTs themselves, etc. Many recent experimental, theoretical and numerical studies in this field are described in detail to uncover the working mechanisms of this new type of strain sensors and to demonstrate some possible key factors for improving the sensor sensitivity.

Fabricating hierarchical core-shell nanostructures is currently the subject of intensive research in the electrochemical field owing to the hopes it raises for making efficient electrodes for high-performance supercapacitors. Here, we develop a simple and cost-effective approach to prepare CuO@MnO2 core-shell nanostructures without any surfactants and report their applications as electrodes for supercapacitors. An asymmetric supercapacitor with CuO@MnO2 core-shell nanostructure as the positive electrode and activated microwave exfoliated graphite oxide (MEGO) as the negative electrode yields an energy density of 22.1 Wh kg−1 and a maximum power density of 85.6 kW kg−1; the device shows a long-term cycling stability which retains 101.5% of its initial capacitance even after 10000 cycles. Such a facile strategy to fabricate the hierarchical CuO@MnO2 core-shell nanostructure with significantly improved functionalities opens up a novel avenue to design electrode materials on demand for high-performance supercapacitor applications.

Solid electrolytes potentially provide safety, Li dendrites blocking, and electrochemical stability in Li-metal batteries. Large efforts have been devoted to disperse ceramic nanoparticles in a poly­(ethylene oxide) (PEO) matrix to improve the ions transport. However, it is challengeable to create efficient framework for ions transport with nanoparticles. Here we report for the first time garnet nanosheets to provide interconnected Li-ions transport pathway in a PEO matrix. The garnet nanosheet fillers would not only facilitate ions transport but also enhance ionic conductivity in comparison with their nanoparticle counterparts. A composite solid polymer electrolyte containing 15 wt % garnet nanosheets exhibits a practically useful conductivity of 3.6 × 10–4 S cm–1 at room temperature. Besides, the composite electrolyte can robustly isolate Li dendrites in a symmetric lithium metal-composite electrolyte battery during reversible Li dissolution/deposition at a relatively low temperature of 40 °C. The symmetric cell with composite electrolyte shows flat voltage and low interfacial resistance over a galvanostatic cycling of 200 h at a current density of 0.1 mA cm–2. A solid-state Li/LiFePO4 battery with the composite polymer electrolyte exhibits a capacity of 98.1 mAh g–1 and a capacity retention of 97.5% after 30 cycles at a temperature of 40 °C. This finding provides a strategy to explore superionic conductors.

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Wearable devices are being intensively investigated in an extensive range of applications, particularly in the field of human motion detection. Herein, a graphene‐modified silk fabric strain sensor is fabricated and its satisfactory performance including high sensibility and comfortable fit to the human body is reported. Graphene oxide is coated on silk fabric by vacuum filtration and is reduced by hot press method, which provides the obtained silk fabric strain sensor with good piezoresistivity and being more environmentally friendly compared with chemical reduction. Meanwhile, compared with the other strain sensors, the silk fabric strain sensor shows a linear and high resistance variation rate with increasing strain. Moreover, the fabric sensor also exhibits other excellent performances, including cycle stability, UV‐blocking, and hydrophobicity to some extent. Owing to the above advantages, the modified silk fabric sensor can be sewed together with fabric and has the potential to detect human motions.