Flexible Al–air batteries have great potential in the field of wearable electronic devices. However, how to reduce the thickness of the battery and improve their applicability in wearable applications is still an unresolved thorny problem. Therefore, this article focuses on the strategies to minimize the thickness of the solid electrolyte for flexible Al–air batteries. In this paper, an innovative aerosol jet printing method is used to prepare the ultrathin neutral electrolyte with a thickness of 18.3–74.5 μm. This study discusses the influence of the thickness and ion concentration on the conductance of the electrolyte in detail. The ultrathin electrolyte has been applied to the flexible Al–air battery, and the battery performance has been explored. The cell pack composed of single cells is light and thin, and can successfully drive small electrical equipment. This study provided new ideas for the preparation of ultrathin electrolyte for flexible energy products.

The hydrogen evolution reaction of the anode is a severe barrier that limits the further commercial application of Al–air batteries. Therefore, this study introduces a bifunctional membrane for the inhibition of hydrogen evolution in Al–air batteries. The reference to Al₂O₃@PAN as “bifunctional” means that it has both hydrophobic and anti-corrosion functions. Al₂O₃ can effectively inhibit the migration of hydroxide ions, and PAN is an excellent hydrophobic material. The bifunctional membrane is placed between the aluminum anode and the electrolyte, which can prevent the invasion of excess water and hydroxide ions, thereby inhibiting the hydrogen evolution corrosion of the anode. Electrochemical tests have confirmed that the corrosion inhibition rate of a bifunctional membrane containing 1.82 wt. % Al₂O₃@PAN is as high as 89.24%. The specific capacity of Al–air batteries containing this membrane can reach 1950 mAh/g, and the utilization rate of the aluminum anode has reached 61.2%, which is helpful in reducing the waste of aluminum resources. The results prove that the bifunctional membrane has excellent anti-corrosion properties. Bifunctional membranes can also be used to prevent the corrosion of metals in other fields.

A novel subband access scheme for multiband high-speed orthogonal frequency division multiplexing (OFDM) passive optical network (PON) is proposed, where the granularity of the bandwidth allocation is as small as the bandwidth of just one subcarrier and the ONUs only receives the desired subcarriers according to the bandwidth allocation strategy from the whole downstream OFDM signal without band limitation. Since the ONUs do not have to receive a complete OFDM band, low-bandwidth and low-speed devices can be used to reduce ONU cost. The algorithm used in the scheme is also explained in detail, and a 1-Tb/s experimental system is successfully established to prove the feasibility of the proposed scheme.

Continuous monitoring of human breathing signals is critical to managing personal healthcare by early detection of health disorders. Wearable and self-powered devices are attracting growing attention as they show great potential for real-time recording of physiological conditions. Conventional breath monitoring is generally recorded through optical fiber sensing, thermal or camera imaging, which is not portable and difficult to achieve continuous monitoring. Herein, an airflow-induced bending sensor based on flexoelectric effect is developed in this study innovatively. The sensor is prepared through a simple electrospinning process using the low cost PVDF and Mn3O4. The response time of the bending sensor is only 45ms, which has obvious advantages over the existing breathing sensors. The breathing sensor prepared in this study can accurately identify different breathing patterns, such as normal, after exercise and coughing. This work paves a way for developing airflow-induced flexoelectric bending sensors with the advantages of fast response, low price, small size and easy to wear, showing potential applications including bending sensing and health monitoring.