Ti–Cr–N Nanopyramid/Nitrogen-Doped Carbon Quantum Dot/Stainless Steel Mesh as a Flexible Supercapacitor Electrode

Abstract

Nitrogen-doped carbon quantum dots (N-CQDs) incorporated into highly conductive transition metal nitrides offer enhanced electrochemical performance, delivering a high energy density and outstanding electrochemical stability. The present study reports a high-performance supercapacitor electrode consisting of electrophoretic anchored zero-dimensional N-CQDs with reactively cosputtered titanium chromium nitride nanopyramid (Ti−Cr−N) thin films on flexible stainless-steel mesh (SSM) substrates. The nanopyramids of N-CQDs/Ti−Cr− N offer remarkable electrochemical performance through Li + storage, ascribed to the abundant electroactive sites and enhanced synergism between the high specific surface area of N-CQDs and higher conductivity of Ti−Cr−N. Subsequently, the N-CQDs/Ti− Cr−N/SSM electrode in a 1 M Li 2 SO 4 aqueous electrolyte exhibits an excellent gravimetric capacitance of 393.8 F•g −1 at a specific current density of 0.32 A•g −1 . Further, the N-CQDs/Ti−Cr−N/SSM heterostructure outperforms other multicationic-based supercapacitors with a maximum energy density of 41.41 Wh•kg −1 and a superior power density of 7.0 kW•kg −1 . Impressive electrochemical stability of ∼88.6% is retained by the heterostructure even after 5000 continuous charge−discharge cycles. Insights into charge storage mechanisms highlight the dominance of surface-limited capacitive and pseudocapacitive kinetics, with fewer contributions from diffusion-controlled faradaic processes. Furthermore, an exemplary mechanical stability of ∼99.98% over 1200 bending cycles demonstrates the N-CQDs/Ti−Cr−N/SSM heterojunction's excellent resilient structural strength, validating the present electrode potential for high-performance flexible supercapacitor application.

Pseudocapacitance Powered Nickel Molybdenum Nitride Nanocomposite Reactively Cosputtered on Stainless-Steel Mesh toward Advanced Flexible Supercapacitors

“…Multiple energy-storing processes function concurrently to offer enhanced electrochemical performance in Ni-Mo-N nanocomposite electrodes. The power law i ( V ) = a ν b is employed to qualitatively separate out the individual charge stored by surface-controlled capacitive and diffusion-controlled Faradaic processes from the total charge storage. ,,, Here, i ( V ) is the voltammetric current at any voltage V , a is a constant, v is the scan rate, and the exponent b is characteristic of the dominant operating mechanism. According to the general capacitor formula, i Cap ( V ) = AC dl ν, b = 1 for surface-dominant capacitive and pseudocapacitive mechanisms.…”

“…According to the general capacitor formula, i Cap ( V ) = AC dl ν, b = 1 for surface-dominant capacitive and pseudocapacitive mechanisms. On the contrary, for diffusion-controlled Faradaic mechanisms, b = 0.5 as per the Randles-Ševčik equation: ,,, i Diff false( V false) = 0.4958 n F A C * D 0.5 true( α n F R T true) 0.5 ν 0.5 To accurately evaluate the charge-storage contributions from slow diffusion-limited processes, the CVs are further scanned at low scan rates (0.1, 0.5, 1, 5, and 10 mV s –1 ). Utilizing the Power law, the slope of a linear-fitted log ν versus log i ( V ) graph can provide the b -value at any anodic/cathodic potential.…”

“…Applying Dunn’s quantitative technique, the total current i ( V ) in the cyclic voltammograms can be deconvoluted into the surface-controlled capacitive current region and diffusion-limited Faradaic current region. Rewriting the power law as ,,, i false( V false) = a ν b = i Cap + i Diff = a 1 ν + a 2 ν 0.5 …”

Multifunctional Resistive Switching in a Magnetization-Graded Ni/NiMnIn/V2O5 Flexible Heterostructure toward Brain-Inspired Neuromorphic Computing

“…The Cu/V 2 O 5 /Ni–Mn–In MIM stack was fabricated employing direct current (DC) magnetron sputtering on a flexible Ni substrate using Ni 50 Mn 35 In 15 , vanadium, and copper commercial targets (Testbourne Ltd., 5 mm thick and 2 in. diameter). − The Ni substrate was ultrasonically cleaned before film deposition. The sputtering parameters used for the deposition of the top electrode (copper, Cu), bottom electrode (Ni–Mn–In), and switching layer (V 2 O 5 ) are mentioned in Table S1 .…”