Large-Scale Production of Flexible, High-Voltage Hydroelectric Films Based on Solid Oxides.

Spontaneous electricity generation through water evaporation is becoming a hot research area. However, low power output, limited material availability, and unscalable fabrication largely hinder its wide applications. Here, we report scalable painting and blade coating approaches for the mass production of flexible hydroelectric films (HEFs) based on solid oxides (e.g., Al2O3), which are of tolerance to mechanical deformation and are compatible with three-dimensional diverse configuration. The electricity power is generated continuously and can last for more than 10 days in ambient conditions. A single HEF unit is capable of supplying an output voltage of more than 2.5 V and even up to 4.5 V at specific conditions. The accumulative energy output can be tuned conveniently by means of series/parallel connections or size control to meet the practical needs of commercial electronics. A family of solid oxides has been verified to have the ability for water evaporation-induced electricity generation, which offers considerable room for the development of high-performance energy-supplying devices.

Built Structure of Ordered Vertically Aligned Codoped Carbon Nanowire Arrays for Supercapacitors.

We report an ingenious yet efficient method to fabricate ordered vertically aligned nitrogen- and sulfur-codoped carbon nanowire (NS-CNW) arrays by direct carbonization of the finely designed copolymer. The as-prepared vertically aligned NS-CNWs with unique electronic features and very narrow diameters facilitate ion diffusion to further exhibit ideal electrochemical properties (243.0 F g-1 at the current density of 0.1 A g-1) and excellent cycle stability (10 000 cycles) when applied to a supercapacitor electrode. The controllable design and copolymerization of conducting polymers, which can provide doped carbon nanowire array electrodes having high surface area with controllable components and uniform dimensions in a neat way, provide more flexibility to tailor the carbon-based electrodes toward specific applications.

Trash to treasure: converting plastic waste into a useful graphene foil.

Recycling of plastic waste has commercial value and practical significance for both environmental safety and recovery of resources. To realize trash recycling, a cheap, simple, and safe solid-state chemical vapor deposition method has been developed to convert a series of daily plastic wastes to a high quality graphene foil (GF) at a large scale. The GF possesses a high electrical conductivity of 3824 S·cm-1, which is much higher than that of the conventional free-standing graphene film treated at an extremely high temperature of 2200-2500 °C. Further, the GF can act as various flexible elements such as a free-standing electrode in a foldable lithium-ion battery, which shows stable electrochemical performances. On the other hand, it presents a fast and ultra low-voltage responsivity to be used as a flexible electrothermal heater, which generates a temperature of up to 322.6 °C at a low input voltage of only 5 V. The convenient trash-to-treasure conversion of plastics to GF provides a unique pathway for waste recycling and opens new application possibilities of graphene in various fields.