ABSTRACT
Sodium-ion batteries (SIBs) have received considerable attention in recent years. Anode material is one of the key factors that determine SIBs' electrochemical performance. Current commercial hard carbon anode shows poor rate performance, which greatly limits applications of SIBs. In this study, a novel vanadium-based material, SrV4O9, was proposed as an anode for SIBs, and its Na+ storage properties were studied for the first time. To enhance the electrical conductivity of SrV4O9 material, a microflower structure was designed and reduced graphene oxide (rGO) was introduced as a host to support SrV4O9 microflowers. The microflower structure effectively reduced electron diffusion distance, thus enhancing the electrical conductivity of the SrV4O9 material. The rGO showed excellent flexibility and electrical conductivity, which effectively improved the cycling life and rate performance of the SrV4O9 composite material. As a result, the SrV4O9@rGO composite showed excellent electrochemical performance (a stable capacity of 273.4 mAh g-1 after 200 cycles at 0.2 A g-1 and a high capacity of 120.4 mAh g-1 at 10.0 A g-1), indicating that SrV4O9@rGO composite can be an ideal anode material for SIBs.
ABSTRACT
We present a straightforward and cost-effective method for the fabrication of flexible photodetectors, utilizing tetragonal phase VO2 (A) nanorod (NR) networks. The devices exhibit exceptional photosensitivity, reproducibility, and stability in ambient conditions. With a 2.0 V bias voltage, the device demonstrates a photocurrent switching gain of 1982% and 282% under irradiation with light at wavelengths of 532 nm and 980 nm, respectively. The devices show a fast photoelectric response with rise times of 1.8 s and 1.9 s and decay times of 1.2 s and 1.7 s for light at wavelengths of 532 nm and 980 nm, respectively. In addition, the device demonstrates exceptional flexibility across large-angle bending and maintains excellent mechanical stability, even after undergoing numerous extreme bending cycles. We discuss the electron transport process within the nanorod networks, and propose a mechanism for the modulation of the barrier height induced by light. These characteristics reveal that the fabricated devices hold the potential to serve as a high-performance flexible photodetector.
