Engineering novel transition metal oxide materials with micro/nanostructures has endowed unusual electrochemical properties. Herein, we reported the MoV2O8/MoO3 microclusters (MVO/MO MCs) synthesized by a simple and facile hydrothermal process. Furthermore, the MVO/MO MC-based electroactive materials were studied at various annealing temperatures of 300, 400, and 500 °C. The prepared materials wrere characterized via different analysis methods for the investigation of phase, morphology, surface area, and oxidation states. The optimized MVO/MO MC electrode revealed a superior specific capacity of 392.58 mAh g−1 at 1 A g−1 (2844 F g−1) in a 1 M KOH electrolyte solution. The MVO/MO MC electrode also exhibited excellent capacity retention of 101% with a corresponding coulombic efficiency of 99%. Accordingly, the fabricated pouch-like asymmetric supercapacitor (ASC) with the MVO/MO MCs and activated carbon materials delivered maximum power and energy densities of 2306.95 W Kg−1 and 37.06 Wh kg−1, respectively. Additionally, the ASC showed superior capacity retention of 128% with 97% of coulombic efficiency. Also, the ASC devices were employed to test the practical application by powering electronic gadgets.

The structural design of electroactive materials including rich profits of high capacitance/capacity and exalted durability is of considerable importance in the development of high-performance wearable energy storage technologies. Herein, a simple and single-step hydrothermal approach is demonstrated to design hierarchical feathers-like microsheet arrays for asymmetric supercapacitors (ASCs) with stable cycling performance. The preparation is carried out at low temperatures without any annealing process, and the as-designed nickel/cobalt vanadate hydrates supported on conductive carbon cloth textile are endowed with the unique architecture of feathers-like microsheets, which allows for the effective contact of active materials, rapid ion diffusion, easy electrolyte penetration, and fast electron transfer. Considering these merits in amalgamation, the Ni0.33Co0.67 vanadate hydrate active material shows a superior areal/specific capacity value of 373.9 µAh cm−2/140 mAh g−1 with outstanding cycling performance (100,000 cycles) than those in the design of mono NiV and CoV hydrates as well as the other fabricated electrode (Ni:Co ratio) materials. Furthermore, the Ni0.33Co0.67 vanadate hydrate active material, when employed as a positive electrode for ASCs, demonstrates excellent electrochemical performance. The assembled ASC exhibits high energy and power density values of 0.19 mWh cm−2 and 2.04 mW cm−2, respectively along with remarkable cycling retention of 82.2% after the completion of 100,000 cycles. Also, the as-assembled device was tested by powering different wearable electronics. This work creates a new pathway for the fabrication of single-step Ni-Co vanadate hydrates for durable electrochemical energy storage applications.

Mechanical energy harvesting from ambient environment has been considered one of the promising technologies for developing autonomous self-powering units, sensors, and various other electronic applications. Triboelectric nanogenerators (TENGs) are one of the recent technologies gaining tremendous interest because of their ability to efficiently harvest ambient energy and convert it into electricity. The phenomenon of the triboelectrification effect in TENGs is not fully understood, along with extracting a maximum electrical output. Herein, we studied the electrification process between two triboelectric films by modulating their charge polarity. The charge polarity in the triboelectric film was modulated without any surface chemical functionalization. A TENG was fabricated to experimentally study the electrification process. Initially, the accepting/donating electrons of a triboelectric film were modulated using fluorine and oxygen atoms contained in polymers and operated against an oppositely charged triboelectric film. After optimizing the electrical output and conducting various stability investigations, the electrical output from the TENG was enhanced. Ultra-low power management integrated circuit (PMIC) implemented in a 180 nm high-voltage BCD (Bipolar CMOS DMOS) process was used. While matching the effective impedance of the TENGs, the PMIC achieves a total energy transfer efficiency of 81.5% utilizing a relatively low input power of 6.5 µW, showing state-of-the-art performance.

Bimetallic oxides are a promising class of noteworthy electrode materials for supercapacitor (SC) application due to the advantages of relatively large surface area, rich electroactive sites, and high electrical conductivity compared to single transition metal oxides (TMOs). Herein, we report bismuth oxide-bismuth manganese oxide (Bi2O3/Bi12Mn12O44 (BBMO)) nanoparticles which were synthesized by adopting a simple solvothermal method. Moreover, the effect of growth time (3, 6, and 9 h) of BBMO materials on their morphology and electrochemical properties was studied systematically. Also, corresponding solitary TMOs were prepared and their electrochemical properties were investigated. Among the prepared electrode materials, the BBMO material synthesized for 6 h (BBMO-6 h) exhibited a superior areal/specific capacity value of 308.7 µAh cm−2/140.3 mAh g−1 at 5 mA cm−2. Additionally, the BBMO-6 h material was used as a positive electrode to construct the hybrid SC (HSC) cell while activated carbon was used as a negative electrode. The constructed HSC cell delivered maximum energy and power density values of 16.7 Wh kg−1 and 1703.3 W kg−1, respectively. Moreover, real-time practical applicability was tested by powering various electronic appliances such as multi-colored light-emitting diodes and a low-rating direct current motor by using the fabricated HSC cell.