Recently, poly(ethylene oxide) (PEO)-based solid polymer electrolytes have been attracting great attention, and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries. In this article, a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries. The PEO-based composite electrolyte is fabricated by hot-pressing PEO, LiTFSI and Ti₃C₂T_x MXene nanosheets into glass fiber cloth (GFC). The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties, good electrochemical stability, and high lithium-ion migration number, which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene. Such as, the GFC@PEO-1 wt% MXene electrolyte shows a high tensile strength of 43.43 ​MPa and an impressive Young's modulus of 496 ​MPa, which are increased by 1205% and 6048% over those of PEO. Meanwhile, the ionic conductivity of GFC@PEO-1 wt% MXene at 60 ​℃ reaches 5.01 ​× ​10⁻² ​S ​m⁻¹, which is increased by around 200% compared with that of GFC@PEO electrolyte. In addition, the Li/Li symmetric battery based on GFC@PEO-1 wt% MXene electrolyte shows an excellent cycling stability over 800 h (0.3 ​mA ​cm⁻², 0.3 ​mAh cm⁻²), which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt% MXene electrolyte with Li anode. Furthermore, the solid-state Li/LiFePO₄ battery with GFC@PEO-1 wt% MXene as electrolyte demonstrates a high capacity of 110.2–166.1 ​mAh g⁻¹ in a wide temperature range of 25–60 ​℃, and an excellent capacity retention rate. The developed sandwich structured GFC@PEO-1 wt% MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

Multifunctional and flexible wearable devices play a crucial role in a wide range of applications, such as heath monitoring, intelligent skins, and human-machine interactions. Developing flexible and conductive materials for multifunctional wearable devices with low-cost and high efficiency methods are highly desirable. Here, a conductive graphene/microsphere/bamboo fiber (GMB) nanocomposite paper with hierarchical surface microstructures is successfully fabricated through a simple vacuum-assisted filtration followed by thermo-foaming process. The as-prepared microstructured GMB nanocomposite paper exhibits not only a high volume electrical conductivity of ~45 ​S/m but also an excellent electrical stability (i.e., relative changes in resistance are less than 3% under stretching, folding, and compressing loadings) due to its unique structure features. With this microstructured nanocomposite paper as active sensing layer, microstructured pressure sensors with a high sensitivity (−4 ​kPa⁻¹), a wide sensing range (0–5 ​kPa), and a rapid response time (about 140 ​ms) are realized. In addition, benefitting from the outstanding electrical stability and mechanical flexibility, the microstructured nanocomposite paper is further demonstrated as a low-voltage Joule heating device. The surface temperature of the microstructured nanocomposite paper rapidly reaches over 80 ​℃ when applying a relatively low voltage of 7 ​V, indicating its potential in human thermotherapy and thermal management.

Thermal conductivity and thermal dissipation are of great importance for modern electronics due to the increased transistor density and operation frequency of contemporary integrated circuits. Due to its exceptionally high thermal conductivity, graphene has drawn considerable interests worldwide for heat spreading and dissipation. However, maintaining high thermal conductivity in graphene laminates (the basic technological unit) is a significant technological challenge. Aiming at highly thermal conductive graphene films (GFs), this prospective review outlines the most recent progress in the production of GFs originated from graphene oxide due to its great convenience in film processing. Additionally, we also consider such issues as film assembly, defect repair and mechanical compression during the post-treatment. We also discuss the thermal conductivity in in-plane and through-plane direction and mechanical properties of GFs. Further, the current typical applications of GFs are presented in thermal management. Finally, perspectives are given for future work on GFs for thermal management.