Bhanu Bhusan Khatua

Hybrid energy storage systems have gained significant attention for addressing rising global energy demands by combining the complementary strengths of batteries and supercapacitors. Their practical implementation, however, requires simultaneous achievement of high energy and power densities, long-term cycling stability, and robust capacitance retention, criteria often limited by the inadequate functionality and structural instability of conventional electrode materials. In this work, a bromine-functionalized nickel-based MOF (Ni-HBTM) containing free carboxylic acid groups was synthesized to overcome these limitations. The Ni-HBTM metal–organic framework (MOF) delivered a specific capacitance of 620.22 F/g at 1 A/g in an alkaline electrolyte. When integrated with reduced graphene oxide (Ni-HBTM@rGO_20), the composite achieved an impressive specific capacitance of 1237.3 F/g at 1 A/g. An asymmetric supercapacitor (ASC) assembled using Ni-HBTM@rGO_20 as the positive electrode exhibited a specific capacitance of 174.04 F/g, energy density of 54.39 Wh/kg at 1 A/g, and a power density of 11,250 W/kg at 15 A/g current densities with 94% capacitance retention after 10,000 cycles, which is a significantly high specific capacitance and power density for Ni-MOF-based composites in comparable conditions. The ASC successfully powered light-emitting diodes (LEDs), demonstrating the potential of functionalized MOF-based materials to bridge the performance gap between batteries and supercapacitors and offering an approach toward next-generation all-solid-state energy storage devices.

A triple‐filler hybrid composite was synthesized based on hydrogenated nitrile butadiene rubber (HNBR) matrix reinforced by white cement (WC), blast furnace slag (SG), and conductive carbon black (CCB). Repurposing the industrial waste as fillers bestowed a semiconducting behavior at remarkably low CCB loadings of 10 phr, whereas DC conductivity values in the range of 10 ⁻⁵ S/cm were achieved—comparable to traditional systems using 40–50 phr CCB. The hybrid composites demonstrated significant improvements in electromagnetic interference (EMI) shielding (up to ~28 dB in the extended Ku band) and gamma radiation shielding (HVL of ~49 and ~60 mm for Ba‐133 and Cs‐137, respectively) compared to the base polymer. Our values outperform conventional concrete and offer a lighter, flexible alternative to steel‐based shields. Mechanical integrity was preserved across all formulations, with optimal samples exhibiting a combination of excellent tensile strength, compressive recovery, and low‐temperature flexibility. Morphological analysis confirmed the presence of interconnected filler networks and enhanced interfacial polarization, critical to the observed multifunctionality. This work establishes a pathway toward leveraging synergistic interactions between industrial waste fillers and minimal conductive additives to obtain composites having applications in next generation lightweight shielding technologies, wearable electronics, and sensors.

The composite 1T MoS ₂ @Cu ₂ S stabilises the 1T phase of MoS ₂ by increasing the interlayer spacing. Its snowflake morphology enhances the electrochemical performance surpassing the limitations of MoS ₂ and shows various real world application.

We developed an eco‐friendly one‐pot method using synthesized NiO‐CuO nanoplates to generate seven‐membered Spiro dibenzo[1,4]diazepine and oxazepine moieties. This three‐component reaction (isatin, 1,2‐phenylenediamine, cyclohexane‐1,3‐dione) proceeds via enamine–imine formation and intramolecular Mannich reaction with water elimination. This method enabled the formation of C─O and C─N bonds, yielding highly substituted Dibenzodiazepine and Dibenzoxazepine derivatives, along with spiro benzodiazepine/oxazepine‐oxindoles containing a quaternary stereogenic center. The use of a recyclable nanocatalyst in an ethanol‐based system ensures a protocol that is both sustainable and environmentally friendly. The synthesized NiO‐CuO nanoplates were extensively characterized using powder XRD, HRTEM, EDX, BET, TGA and ICPMS. This approach benefits from easily accessible starting materials and a cooperative synergistic interaction in a bimetallic oxide nanocatalyst, operating under mild conditions. Leaching tests confirmed its heterogeneous nature and the catalyst was reused for eight cycles. The reaction accommodates a broad range of substrates, demonstrating versatility with the supported catalyst.

The rapid expansion of wearable, portable electronics has encouraged scientists to create flexible, self-powered gadgets with energy-harvesting capabilities. Here, we designed a PVDF composite-based flexible piezoelectric nanogenerator through stabilization of the polar beta phase of the PVDF polymer using fly ash, a hazardous waste product. We were able to stabilise the PVDF's β-phase without the need for external electrical polling by employing this filler. Negative surface charge of the fly ash facilitates the β-phase stabilization in PVDF by means of electrostatic contact. A flexible fly ash/PVDF composite using 15 wt% calcined fly ash was prepared using a low-cost solution casting technique. The fly ash can successfully stabilize the β-phase of the PVDF polymer up to ∼90%. The CFA/PVDF composite was subsequently moulded and positioned between the copper electrodes. Under a human finger pressure of around 20 kPa, the manufactured waste material-based piezoelectric nanogenerator (WPNG) can produce up to ∼27 V of voltage and 0.3 μA of current. In addition, the WPNG can generate a power density of 9.11 μW cm⁻² at a resistance of 10 MΩ, which is sufficient enough to power up other tiny devices like calculators, speakers, and wristwatches, as well as charge capacitors and illuminate LEDs. The fabricated nanogenerator shows almost the same output performance even after four weeks.