Gagan Kumar Sharma

Changing the Ar/O ₂ flow ratio at the gas inlet leads to an increase in TCR at low-temperature deposition in a sputtering chamber.

To overcome the limitations of commercializing lithium‐ion batteries (LIBs), a one‐step feasible route is reported to prepare a hybrid matrix of molybdenum oxides (MoO _3‐x , x = 0 and 1) thin film anode. In this direction, the electrical conductivity barriers of MoO ₃ dielectric are overcome by reinforcing conductive MoO ₂ via the chemical vapor deposition (CVD) route. The intermixed array of nanograins and nanoflakes grown over stainless‐steel (SS) foil delivers a maximum gravimetric capacitance of 281 F g ⁻¹ and a specific capacity of 348 mAh g ⁻¹ at 1 A g ⁻¹ . The synergistic integration of metal oxides facilitates multiple valencies, interfacial structural stability, and abundant ion transport channels to achieve a wider voltage window of 3.50 V. Subsequently, the prepared Li||MoO ₂ ‐MoO ₃ @SS configuration possesses electric double‐layer and pseudocapacitive energy storage capacity leading to remarkable specific energy 77.78 Wh kg ⁻¹ and excellent specific power 13.75 kW kg ⁻¹ . The high‐rate capacity tests for continuous 1200 charge–discharge cycles disclose retention of ≈88% and ≈100% Coulombic efficiency on a 2‐fold enlargement of current density. The longer lifespan and higher rate capacity of nanohybrid anode owing to reversible lithiation/delithiation further recommend its candidacy in developing LIBs for next‐generation portable electronics.

A hybrid supercapacitor/battery device is proposed by integrating Na₃V₂(PO₄)₂F₃ and multi‐walled carbon nanotubes as the battery electrode and carbon nanofiber as a supercapacitor electrode. The device made via the slurry casting of electrode material on foldable thin nickel foils leads to a robust, mechanically flexible sodium‐ion capacitor/battery (supercapattery) as a hybrid energy storage system. The device exhibits a specific capacitance of 136 F g⁻¹ with a corresponding specific capacity of 95 C g⁻¹ at a potential scan rate of 1 mV s⁻¹, a maximum working voltage of 0.70 V, and a power density of 15 kW kg⁻¹ at 2.50 Wh kg⁻¹. Mechanical flexibility tests show practically unperturbed electrochemical properties at significant bending angles of up to 160°, indicating excellent robustness during large‐scale device deformation. The current study offers new avenues to develop energy storage systems for next‐generation portable and wearable energy storage devices that can be integrated into a variety of platforms.

The prevailing challenges in developing flexible electronic devices are breaking contacts and perturbed responses during bending operations. This work uses a facile method to fabricate the embedded and firm back contact for flexible electronic devices. The polyvinyl alcohol (PVA) solution in distilled water is employed to synthesize the environment-friendly bendable substrate. The partially embedded back contact using copper wire was made during the substrate development. For connection and flexibility checks, silver (Ag) and molybdenum disulfide (MoS ₂ ) were sputter-coated over the flexible substrate, and different current-voltage (I-V) measurements were performed. The results showed excellent contact between the partially embedded copper wire and the deposited thin films. For bending characterization, the I-V measurements at different angles (0° to 180°) have been carried out for both materials. It revealed the overlapping plots for all angles, suggesting an unperturbed bending response. For practical demonstration, the flexible substrate with partially embedded interdigitated electrodes (IDE) was fabricated over which a thick film of zinc oxide (ZnO) nanoplates was coated. The IV measurements in flat-bend-flat cycles revealed an enhanced current due to the piezoelectric nature of ZnO in bending states and a full recovery in flat states. Therefore, the as-fabricated device can be considered cost-effective and ready to use as a body-arms movement sensor for medical applications. The developed flexible substrate with embedded contacts facilitating robust electrical connections can also be employed in various electronic devices such as gas sensors, photodetectors, supercapacitors, etc.

By combining the exclusive characteristics of a two-dimensional MoS₂ layered material with a conventional key material, aluminum nitride (AlN), a flexible supercapacitor electrode can be realized. We present a bendable electrode that is straightforwardly grown on stainless-steel foil via a binder-free sputtering route. The inherent merits of good conductive pathways among MoS₂ nanolayers and enriched pseudocapacitive and dielectric activity from AlN nanoflowers enable synergism of the intermixed porous structure. This unique surface morphology facilitates sulfur and nitrogen edges to make insertion/de-insertion of Li-ions more feasible to store electrochemical energy. The MoS₂[email protected] hybrid working electrode achieves a gravimetric capacitance of 372.35 F/g at a 5 mV/s scan rate with a wide potential window of 2 V in a 1 M Li₂SO₄ electrolytic aqueous solution. The composite thin film of better adhesion with the current collector exhibits a remarkably high specific power of 28.05 W h/kg at a specific power of 0.26 kW/kg, simultaneously an advanced cycling lifespan of 93% over 5000 charge–discharge cycles. The capacity of the hybrid electrode is almost unperturbed under bending from 0° to 175°, while only ∼5% degradation in capacitance was noticed at a flexing angle of 175°. These distinctive features of this electrode material elucidate the practical applicability and recommend it as a promising candidate in wearable bendable supercapacitors.

We report the fabrication of binder-free, low-cost and efficient hybrid supercapacitive electrode based on the hexagonal phase of two-dimensional MoS ₂ nanoworms reinforced with molybdenum nitride nanoflakes deposited on stainless steel (SS) substrate using reactive magnetron sputtering technique. The hybrid nanostructured MoS ₂ –Mo ₂ N/SS thin film working electrode delivers a high gravimetric capacitance (351.62 F g ⁻¹ at 0.25 mA cm ⁻² ) investigated in 1 M Na ₂ SO ₄ aqueous solution. The physisorption/intercalation of sodium (Na ⁺ ) ions in electroactive sites of MoS ₂ –Mo ₂ N composite ensures remarkable electrochemical performance. The deposited porous nanostructure with good electrical conductivity and better adhesion with the current collector demonstrates a high-energy density of 82.53 Wh kg ⁻¹ in addition to a high-power density of 24.98 kW kg ⁻¹ . Further, excellent capacitance retention of 93.62% after 4000 galvanostatic charge–discharge cycles elucidated it as a promising candidate for realizing high-performance supercapacitor applications.

Rationally engineered three-dimensional (3D) clusters of MoS₂ nanowires vertically anchored over a nanostructured NiTiCu shape memory alloy are fabricated using magnetron sputtering for flexible thin film supercapacitive electrodes. The heterostructure MoS₂/NiTiCu deposited directly over flexible stainless steel (SS) offers remarkable electrochemical performance along with excellent mechanical stability, arising synergistically from the large specific surface of MoS₂ nanowires and a high mechanical strength of [email protected] The electrochemical studies in sulfate electrolytes (Li₂SO₄ and Na₂SO₄) manifest dominant charge transport efficiency of Li⁺ into the easily accessible electroactive sites of MoS₂. The electrode delivers a superior gravimetric capacitance (379.25 F/g at 0.78 A/g) in addition to outstanding cycling stability (95.9% over 5000 cycles), suggesting high Li⁺ conductivity, low equivalent series resistance, and good substrate adhesion. Furthermore, the Power law and Dunn's approach reveal that charge storage into the highly porous MoS₂ networks occurs mainly through the pseudocapacitive mechanism in Li₂SO₄ and capacitive processes in Na₂SO₄. Practically flexing the working electrode over 1000 bending cycles degrades the capacitance by only 17.17%, achieving highly desirable mechanical stability. Significantly, a superior power density of 12.54 kW/kg, while simultaneously achieving a high energy density of 52.67 Wh/kg, presents the electrode's immense potential for high-performance supercapacitor devices in flexible electronics.

Here, we present a binder less sputtering approach for controllable growth of copper nitride (Cu₃N) nanoflakes incorporated into 2D layered molybdenum disulfide (MoS₂) nanoworms directly grown on flexible stainless steel (SS) substrate. The formation of the intermixed nanostructure is revealed by surface morphology. Moreover, the porous structure and good conductivity, and the presence of sulfur and N₂ edges facilitate the synergistic effect favor more pathways for insertion and desertion of electrolyte ions (Na⁺). The optimized composite electrode achieves an outstanding specific capacitance (215.47 F/g at 0.5 A/g) along with remarkable elongated cycle life (∼90% retention over 2000 cycles at 9.5 A/g). Additionally, the electrode (of dimensions 3 × 1 cm²) shows high energy density (∼30 Wh/kg at a power density of 138 W/kg), extended potential window (1 V), fair mechanical stability, and pliability (retains ∼91% specific capacitance at 175° bending angle). The contemporary method provides a cathode material for practically applicable supercapacitors with superior flexibility and desirable electrochemical properties.