Specific Capacity Research Articles

In situ synthesis of M (Fe, Cu, Co and Ni)-MOF@MXene composites for enhanced specific capacitance and cyclic stability in supercapacitor electrodes

In this study, an in situ method was developed to synthesize a series of uniform 3D MOFs (Fe-, Cu-, Co-, Ni)-BTC@2D MXene (Ti3C2Tx) composites, and the experimental results show that a typical sample of Ni-MOF@MX 2 exhibits the highest specific capacitance of 1160.5 F·g−1 and 736 F·g−1 at a current density of 1 A·g−1 and 20 A·g−1, respectively, which is 2.3 times higher than the value of 320 F·g−1 at a current density of 20 A·g−1 on the bare Ni-MOF, and particularly maintains significant cyclic stability after 10,000 cycles at a high current density of 20 A·g−1. The improved electrochemical performance is ascribed to the synergistic interaction between layered MXene and MOFs, which were evidenced by experiments and theoretical calculations. The Ni-MOF@MX 2//AC asymmetric supercapacitor (ASC) device demonstrates a maximum energy density of 48.2 Wh kg−1 at 750 W kg−1. It retains 94 % capacity after 10,000 cycles. Moreover, the value still maintained at 23.3 Wh·kg−1 when elevating power density to 15000 W·kg−1. This indicates that the obtained MOF@MXene composites are probably alternative materials for supercapacitor electrodes in energy storage.

Structural and Electrochemical Evolution of Water Hyacinth-Derived Activated Carbon with Gamma Pretreatment for Supercapacitor Applications.

This study introduces a gamma pretreatment of water hyacinth powder for activated carbon (AC) production with improved electrochemical properties for supercapacitor applications. The structural and morphological changes of post-irradiation were meticulously analyzed using scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The pretreatment significantly modifies the pore structure and reduces the particle size of the resulting activated carbon (WHAC). Nitrogen adsorption-desorption isotherms indicated a substantial increase in micropore volume with escalating doses of gamma irradiation. Electrochemically, the activated carbon produced from pretreated WH at 100 kGy exhibited a marked increase in specific capacitance, reaching 257.82 F g-1, a notable improvement over the 95.35 F g-1 of its untreated counterpart, while maintaining 99.40% capacitance after 7000 cycles. These findings suggest that gamma-pretreated biomasses are promising precursors for fabricating high-performance supercapacitor electrodes, offering a viable and environmentally friendly alternative for energy storage technology development.

Sulfonated polyaniline/MXene composite electrode with high cycling stability for anti-freezing flexible supercapacitor

Polyaniline (PANi) is widely used in supercapacitors owing to its unique structural flexibility and redox behavior. However, due to the limitations of the inherent molecular structure, the expansion and contraction of the PANi skeleton will be triggered during the charging and discharging process, leading to decreased stability and rapid degradation. For this reason, we design a novel sulfonated polyaniline structure of aniline copolymerized with 2-aminobenzenesulfonic acid, thus immobilizing the sulfonic acid group (−SO3H) side chain onto the PANi main chain. The −SO3H acts as a proton reservoir to provide protons for PANi, accelerating the occurrence of redox reactions and providing pseudocapacitance, effectively suppressing the deprotonation phenomenon. Then SPANi is grown in-situ on the interlayers of MXene, which induces the disordered polymer to be ordered on the MXene substrate, forming a 3D interconnected network composite with both high specific capacitance and excellent stability. SPANi/MXene composite has an outstanding specific capacitance of 512.45 F g−1 at 1 A/g and retains up to 92.16 % of the initial capacitance after 10,000 cycles. Assembled with PHEAA-PAA-MXene double-crosslinked organogel electrolyte to form an anti-freezing device with a specific capacitance of 158.63 F g−1, it retains a high specific capacitance of 118.26 F g−1 even under the extreme conditions of −40 °C. The capacitance retention after 10,000 cycles is 95.2 % (20 °C) and 81.82 % (−40 °C), respectively. This work provides simple and effective methods to fabricate high-performance PANi-based electrodes and anti-freezing supercapacitors.

Novel in-situ encapsulation of tin phosphide particles in MXene conductive networks as anode materials of the durable sodium-ion battery

Sodium-ion battery (SIB) is one of potential alternatives to lithium-ion battery, because of abundant resources and lower price of sodium. High electrical conductivity and long-term durability of MXene are advantageous as the anode material of SIB, but low energy density restricts applications. Tin phosphide possesses high theoretical capacity, low redox potential, and large energy density, but volume expansion reduces its cycling stability. In this study, tin phosphide particles are in-situ encapsulated into MXene conductive networks (SnxPy/MXene) by hydrothermal and phosphorization processes as novel anode materials of SIB. MXene amounts and hydrothermal durations are investigated to evenly distribute SnxPy in MXene. After 100 cycles, SnxPy/MXene reaches high specific capacities of 438.8 and 314.1 mAh/g at 0.2 and 1.0 A/g, respectively. The capacity retentions of 6.0% and 73.6% at 0.2 A/g are respectively obtained by SnxPy and SnxPy/MXene. The better specific capacity and cycling stability of SnxPy/MXene are attributed to less volume expansion of SnxPy during charge/discharge processes and relieved self-stacking of MXene by encapsulating SnxPy particles between MXene layers. Electrochemical impedance spectroscopy and Galvanostatic intermittent titration technique are also applied to analyze the charge storage mechanism in SIB. Higher sodium ion diffusion coefficient and smaller charge-transfer resistance are obtained by SnxPy/MXene.

Enhanced Stability-Based Hydroxymethyl Cellulose/Polyacrylamide Interpenetrating Dual Network Hydrogel Electrolyte for Flexible Yarn Zinc-Ion Batteries

As the field of wearable electronics continues to boom, the demand for flexible energy storage devices continues to grow. However, the development of soft energy supply devices with excellent stability is still a challenging task. Traditional hydrogel electrolytes are prone to mechanical deformation, which makes it difficult to maintain the functional stability of flexible yarn due to its short battery life and low wear resistance. Here, we developed a reversible energy-dissipating dual-network hydrogel electrolyte. The hydroxymethyl cellulose (CMC)/polyacrylamide (PAM) hydrogel electrolyte has a tensile deformation of 2700% and a high ionic conductivity of 6.37 × 10−2 S cm−1. The specific capacity of the assembled CMC/PAM-based yarn cell was 170 μAh cm−1 at 1 mA cm−1 and 73.14% after 100 cycles. The excellent performance is attributed to the crosslinked double network structure, in which the introduction of carboxyl groups is conducive to the improvement of hydrophilicity and ionic conductivity. The hydrogen bond and reversible CMC macromolecular chain can be restored after stress relief, which greatly improves the toughness of the material. Even under different bending angles and repeated bending conditions, zinc yarn batteries still have outstanding mechanical properties and cycle stability (71.28% specific capacity after 100 cycles), showing broad application prospects in wearable smart textiles.

Hierarchical core-shelled CoMo layered double hydroxide@CuCo2S4 nanowire arrays/nickel foam for advanced hybrid supercapacitors

The development of core-shelled heterostructures with the unique morphology can improve the electrochemical properties of hybrid supercapacitors (HSC). Here, CuCo2S4 nanowire arrays (NWAs) are vertically grown on nickel foam (NF) utilizing hydrothermal synthesis. Then, CoMo-LDH nanosheets are uniformly deposited on the CuCo2S4 NWAs by electrodeposition to obtain the CoMo-LDH@CuCo2S4 NWAs/NF electrode. Due to the superior conductivity of CuCo2S4 (core) and good redox activity of CoMo-LDH (shell), the electrode shows excellent electrochemical properties. The electrode’s specific capacity is 1271.4C g−1 at 1 A g−1, and after 10, 000 cycles, its capacity retention ratio is 92.2 % at 10 A g−1. At a power density of 983.9 W kg−1, the CoMo-LDH@CuCo2S4 NWAs/NF//AC/NF device has an energy density of 52.2 Wh kg−1. This indicates that CoMo-LDH@CuCo2S4/NF has a great potential for supercapacitors.

Tuning the microstructure of biomass-derived hard carbons by controlling the impurity removal process for enhanced Na ion storage performance

Biomass-derived hard carbons are promising anode materials of sodium-ion batteries (SIBs) due to their low cost, renewability and high specific capacity. However, there are inevitably some impurities in biomasses that may not only affect the purity, but microstructure and electrochemical performance of hard carbons. Although the impurities can be removed by appropriate treatments after carbonization, the microstructure of hard carbons can hardly be changed. In this work, taking ficus macrophylla leaves (FMLs) as the model biomass, the effects of impurities and their removing process on the microstructure and Na ion storage performance of hard carbons are investigated. It is found that the presence of Ca and Si-bearing impurities in FMLs results in more graphite-like structure in hard carbons because of their catalytic graphitization effect. The acid and base washing processes after carbonization can mostly get rid of the inorganic impurities is unable to increase the plateau region capacities associating to Na ion insertion in the interlayer of graphitic microcrystals and Na metal filling in micropores. By contrast, by stepwisely removing the Ca and Si-bearing impurities from raw materials before carbonization, hard carbons with high purity, larger interlayer space and more micropores are produced, which exhibit a high reversible specific capacity of 336 mAh g−1 at 20 mA g−1, a high initial Coulombic efficiency of 93 %, excellent rate capability (245 mAh g−1 at 2 A g−1) and robust cycle stability. This study implies that controlling the impurity removal process can simultaneously tune the microstructure of hard carbon anodes derived from biomasses towards high performance Na ion storage.

Hierarchical core-shelled CoMo layered double hydroxide@CuCo2S4 nanowire arrays/nickel foam for advanced hybrid supercapacitors

The development of core-shelled heterostructures with the unique morphology can improve the electrochemical properties of hybrid supercapacitors (HSC). Here, CuCo2S4 nanowire arrays (NWAs) are vertically grown on nickel foam (NF) utilizing hydrothermal synthesis. Then, CoMo-LDH nanosheets are uniformly deposited on the CuCo2S4 NWAs by electrodeposition to obtain the CoMo-LDH@CuCo2S4 NWAs/NF electrode. Due to the superior conductivity of CuCo2S4 (core) and good redox activity of CoMo-LDH (shell), the electrode shows excellent electrochemical properties. The electrode’s specific capacity is 1271.4C g−1 at 1 A g−1, and after 10, 000 cycles, its capacity retention ratio is 92.2 % at 10 A g−1. At a power density of 983.9 W kg−1, the CoMo-LDH@CuCo2S4 NWAs/NF//AC/NF device has an energy density of 52.2 Wh kg−1. This indicates that CoMo-LDH@CuCo2S4/NF has a great potential for supercapacitors.

A pseudo-2-dimensional model of the nonlinear impedance response of a nickel-iron battery

Abstract Pseudo-2-dimensional (P2D) models are computationally efficient tools for accurately predicting the battery’s performance. These models have been widely used to simulate lithium-ion batteries, but their application can be extended to other battery chemistries. Nickel-iron batteries are one type of storage that is regaining attention due to their durability and large theoretical specific capacity. However, their tendency to form an irreversible passivation layer and hydrogen gas leads to lower overall specific capacity and charging efficiency. Physics-based models of impedance spectra can help understand and interpret mass transport, thermodynamic, and reaction processes in a system. Batteries, being nonlinear systems in nature, can be better evaluated through nonlinear electrochemical impedance spectroscopy (NLEIS), an extension of the traditional electrochemical impedance spectroscopy (EIS), to break the degeneracy of a linear model. Base case parameters were used to generate the impedance spectra by applying moderate-amplitude current modulations. This work compared the first harmonic linear response and the second harmonic nonlinear response simulated through a P2D model. Unlike EIS, the nonlinear response shows sensitivity to charge transfer symmetry. At the negative electrode, the nonlinear response demonstrates strong dependence on the kinetic properties, suggesting that the overall battery performance is mainly influenced by the processes at the negative electrode-electrolyte interface.

The effect of thermoelectric augmentation dramatically increased the specific capacity for electrochemical energy storage

Conventional methods to enhance the performance of electrode materials include morphological modification and defect engineering, but the limited number of active sites for the electrode remains a huge obstacle to achieving high-performance supercapacitors. In this work, we proposed a strategy to improve the electrode performance under the condition of limited active sites through the thermoelectric effect, and designed thermoelectric electrodes of the p-type Fe0.3Co0.7Sb3 cathode and the n-type Cu0.3Ag1.7Se anode for supercapacitors, respectively. In particular, the charge carriers generated by the thermoelectric effect accelerate the electrochemical reaction process at the interface between the thermoelectric electrode and the electrolyte under the temperature difference (ΔT) condition, thus increasing the specific capacity of the electrode. The p-Type Fe0.3Co0.7Sb3 cathode and the n-Type Cu0.3Ag1.7Se anode exhibit a 150% and 208% increase in the specific capacity, respectively. Furthermore, electrodes with different conduction types and various thermoelectric properties, such as n/p-type bismuth telluride and n/p-type half-Heusler thermoelectric materials are also studied, confirming the universality of the above phenomenon in thermoelectric electrodes. This work provides a universal route for the thermoelectric effect to promote the energy density of supercapacitors used in high temperature difference environments.

Experimentally validated screening strategy for alloys as anode in Mg-air battery with multi-target machine learning predictions

The anode in Mg-air cell plays the important role in determining the overall discharge performance. To refine the Mg-air cell performance, numerous Mg alloys have been developed in past decades by extensive trial-and-error efforts. However, it is a tough task to determine the suitable elements and their compositions to fabricate the Mg alloys with the expected feature. Machine learning (ML), as a hot artificial intelligence technology, has shown significant potential in screening and predicting the new materials. Herein, a machine learning (ML) model is trained via Extreme Gradient Boosting Regressor (XGB) algorithm to assist the exploration of binary Mg alloys that is suitable to be efficient anode in Mg-air cell. Importantly, four metrics related with magnesium-air batteries: cell voltage, utilization efficiency, specific capacity, and specific energy, are all considered to screen out the promising Mg anodes instead of depending on only one feature. After that, five potential Mg alloys, Mg-Ca, Mg-Zn, Mg-Sn, Mg-Al, and Mg-Li, are fabricated according to the machine learning results and their discharge performance is determined. The different discharge performance of above five anodes are elucidated by the emission scanning electron microscope (SEM), potentiodynamic polarization curves (PDP), and real-time hydrogen evolution measurement. The Mg-Ca anode exhibits the highest specific energy of 1797.1 Wh kg−1 at 10 mA cm−2, while the Mg-Li anode has the worst discharge performance. It is consistent with the predicted results by machine learning. Overall, this work breaks through the limitations of traditional material design, offering new insights for the development of magnesium-air batteries, which could be extended to other materials.

Multilayer Ti3C2Tx-loaded CoOHF composite structures for high-performance lithium-ion batteries

Research into new composites to enhance the performance of lithium-ion battery electrode materials has become a trendy area of study. Cobalt-based composites are particularly prominent due to their exceptional electrochemical performance and unique physicochemical properties. Additionally, Ti3C2Tx MXenes materials are anticipated to replace graphene and other carbonaceous materials since they possess an open structure and low lithium-ion diffusion barrier. In this work, we employed simple hydrothermal method to combine layered Ti3C2Tx with needle-shaped CoOHF. The resulting nanosheets showed an even dispersion of CoOHF in the surface, leading to a remarkable increase in specific capacity. Furthermore, Ti3C2Tx provided a higher number of lithium-ion active sites and improved the lithium-ion migration rate, while also ensuring the structure and stability of CoOHF. This composite material enables stable cycling for 1000 cycles at high current densities of 2 A g−1 and ultimately shows a large capacity of 802.4 mAh g−1 stably. Additionally, CoOHF/MXene composites display exceptional performance rate and cycling stability. This study highlights new feasible strategies for using multilayer Ti3C2Tx in lithium-ion batteries, along with metal hydroxyfluorides in new, highly efficient lithium-ion battery anode materials.

Tuning the microstructure of biomass-derived hard carbons by controlling the impurity removal process for enhanced Na ion storage performance

Biomass-derived hard carbons are promising anode materials of sodium-ion batteries (SIBs) due to their low cost, renewability and high specific capacity. However, there are inevitably some impurities in biomasses that may not only affect the purity, but microstructure and electrochemical performance of hard carbons. Although the impurities can be removed by appropriate treatments after carbonization, the microstructure of hard carbons can hardly be changed. In this work, taking ficus macrophylla leaves (FMLs) as the model biomass, the effects of impurities and their removing process on the microstructure and Na ion storage performance of hard carbons are investigated. It is found that the presence of Ca and Si-bearing impurities in FMLs results in more graphite-like structure in hard carbons because of their catalytic graphitization effect. The acid and base washing processes after carbonization can mostly get rid of the inorganic impurities is unable to increase the plateau region capacities associating to Na ion insertion in the interlayer of graphitic microcrystals and Na metal filling in micropores. By contrast, by stepwisely removing the Ca and Si-bearing impurities from raw materials before carbonization, hard carbons with high purity, larger interlayer space and more micropores are produced, which exhibit a high reversible specific capacity of 336 mAh g−1 at 20 mA g−1, a high initial Coulombic efficiency of 93 %, excellent rate capability (245 mAh g−1 at 2 A g−1) and robust cycle stability. This study implies that controlling the impurity removal process can simultaneously tune the microstructure of hard carbon anodes derived from biomasses towards high performance Na ion storage.

Uncovering the freezing energy release of salted grass carp (Ctenopharyngodon idella) flesh: Effects of water state and protein structure on the thermal properties

The effect of NaCl content on the protein structures, water status and thermal properties of grass carp flesh, along with its relationship with energy required for freezing was investigated to improve the quality of frozen flesh and to reduce energy consumption for freezing. Adding salt prompted the shifting of the secondary structure of α-helix to β-sheet, β-turn and random coil. The interaction between water molecules and hydrophilic groups in the unfolded protein structure increased nonfreezing water content, which decreased specific heat capacity, thermal conductivity of sample during freezing. The lowest energy required (235.69 kJ/kg) for freezing was found in 7% NaCl salted sample, indicating a 38.39% reduction compared to the unsalted sample. Few pores between muscle fibers were observed in the 3% and 5% NaCl salted sample. Therefore, an optimal salt concentration improved quality of frozen flesh and reduced the energy required for freezing, promoting energy-efficient freezing of aquatic products.

Synthesis of heat-integrated water networks considering detailed heat exchanger design

This paper introduces a mathematical programming approach for synthesising heat-integrated water networks (HIWNs) with a detailed heat exchanger design. A common assumption of constant heat capacities of water streams is relaxed. The specific heat capacity of water is now considered as a nonlinear function of temperature to avoid errors in calculating energy balances. In addition, most previous works have assumed constant individual heat transfer coefficients for water streams and utilities when estimating heat transfer areas. This assumption can lead to significant over- or under-estimation of heat transfer areas. In this research, individual and overall heat transfer coefficients for heat exchangers are calculated based on the detailed design of plate heat exchangers for heat recovery. The objective function of the proposed mixed integer nonlinear programming (MINLP) model is to minimise the total annualised cost (TAC). The TAC includes operating costs for freshwater and utilities, pumping costs for overcoming pressure drops in heat exchangers, and investment costs for heat exchangers. Three examples are solved in this work to verify the proposed model.

Theoretical analysis of using multiple borehole heat exchangers for production of heating and cooling energy in shallow geothermal reservoirs with underground water flow

In this work the feasibility of using the double-U borehole heat exchangers (BHE) in multiple arrangements for production of heating and cooling energy has been investigated.Theoretical case studies are given for a few hypothetical lithological cases corresponding to the lithology that can be found in City of Zagreb. The results show interference between the borehole heat exchangers and limits of use of shallow reservoir with respect to slow convection and loss of accumulated energy in the reservoir. Special emphasis is placed on the description of the groundwater flow determined by the parameters of the shallow geothermal reservoir, such as permeability, water saturation, thermal conductivity, specific heat capacity and soil density, topography, precipitation, etc. Simulations have been performed in FeFlow coupled with Python user-scripts for individual control of the BHE’s, and the surface equipment is modelled using RES2GEO. To assess the accuracy of numerical predictions in simulating thermal responses, FeFlow software was utilized to conduct Thermal Response Tests (TRT) for individual Borehole Heat Exchangers (BHEs). These numerical results were then juxtaposed with empirical TRT data collected from a site near Velika Gorica, a town within the City of Zagreb. For each case simulation is done for one year with one hour resolution. The temperature distribution analysis highlights notable differences between scenarios, where the temperature field with lower permeability experiences significant variations, particularly near the BHE. Here, temperatures can soar to 20 °C during cooling periods and plummet to 4 °C in heating seasons. These fluctuations cause overheating and subcooling of the reservoir, impairing the heat pump’s efficiency and necessitating increased electricity consumption. By using Multivariate linear regression and Multi-layer perceptron regressor method, the main parameter for determination of COP of ground source heat pump. The analysis reveals that the majority of errors fall within the range of ± 5 %, although the MLA prediction method exhibits slightly more frequent errors. Additionally, the R2 scores demonstrate strong performance: the MLA procedure achieves 0.95 for heating and 0.99 for cooling, while the MLP procedure attains 0.99 for both heating and cooling phases.

A minimalist elastic metamaterial with meta-damping mechanism

A novel elastic mechanical metamaterial with extreme damping performance has been achieved skillfully by coupling snap-through and pseudo-constant-force behaviors. The proposed meta-damping mechanism is systematically expounded to tailor synthetical force–displacement response for programming hyper energy dissipations. Within this framework, detailed designs in functional sub-structures and collaborative design strategy combined with parametric optimization in integrated structure are further presented synthetically. By additive manufacturing and loading–unloading cyclic experiments, the physical realization of meta-damping elastic metamaterials reveals the extraordinary specific damping capacity (Ψ=7.03), which exceeds any research reported previously and is immensely close to the theoretical limit. Remarkably, this minimalist design method, with only two necessary functional components, reconciles the contradiction between load-bearing and damping dissipation, with strong multi-directional and periodic expansibility. This work has far-reaching implications on the compact design of recoverability, reusability, frequency-independent, material-independent elastic mechanical metamaterials for superior dynamic applications such as impact absorption vibration reduction, and energy trapping.

Hierarchical CaZrO3@rGO nanostructure as an electrode material for high-performance supercapacitor devices

The primary focus of energy-storage system development is to find cost-effective solutions that improve performance, efficiency and stability. The electrode composed of CaZrO3 nanoparticles supported by reduced graphene oxide demonstrates higher capacitance and long-term cyclic stability. In this work, CaZrO3@rGO nanocomposite synthesized through a hydrothermal approach exhibited a specific capacitance of 1564 F/g @ 1 A/g with lower charge transfer resistance of 0.2 Ω which showed cyclic stability after 10,000th cycles. Due to the increased surface area and enrichment of active zones, the capacitive properties of the electrode are greatly improved when metal oxides are combined with rGO. Based on these results, it seems that CaZrO3@rGO nanocomposite may be used for future energy-saving equipment.

Study on the properties of electrode materials for supercapacitors based on 1D Co-MOCPs

Three one-dimensional (1D) Co-MOCPs (23PCo-S1, 23PCo-S2, and 23PCo-S3; where 23P denotes the ligand, 2,3-pyridine dicarboxylic acid) were synthesized using a similar hydrothermal method. The molecular formulas for the isomers 23PCo-S1 and 23PCo-S2 are [Co(23P)3H2O], while that for 23PCo-S3 is [Co(23P)2H2O]. These single-crystal structures are classified into the P-1, Pca21, and P21/c space groups, displaying triclinic, orthogonal, and monoclinic symmetries, respectively. Techniques such as S-XRD, P-XRD, XPS, and SEM were applied to analyze the structures and valence states of the materials. Additionally, the electrochemical properties of the structures were evaluated using a three-electrode setup. Among these, 23P-Co-S2 demonstrated a remarkable specific capacitance of 458.5 F g–1 at a current density of 1 A g–1. In contrast, 23P-Co-S1 and 23P-Co-S2 showed specific capacitances of 192.2 and 270.6 F g–1, respectively, under the same experimental conditions.

Fusarium oxysporum mediated synthesis of nitrogen-doped carbon supported platinum nanoparticles for supercapacitor device and dielectric applications

A scalable method has been developed for synthesizing nitrogen-doped carbon-supported platinum nanoparticles. Fusarium oxysporum was utilized as reducing and stabilizing agent, and calcination was employed to produce the carbon support. The unique properties of Fusarium oxysporum facilitate the reduction of metal ions while preventing agglomeration and maintaining nanoparticle stability. An extensive investigation of the electrochemical supercapacitor and temperature-dependent dielectric properties of the nanoparticles demonstrates their suitability for supercapacitor applications. Electrochemical analysis showed N-doped C/Pt NPs with high specific capacitance, 482.77F/g at 2.0 A/g, retaining 94 % capacitance even under 20 A/g after 10,000 cycles. The symmetric supercapacitor device displayed 275F/g at 2 A/g, maintaining 61.10 Wh/kg energy density at 1000 W/kg power density, with ∼ 92 % capacitance retention after 10,000 cycles. Dielectric properties of N-doped C/Pt NPs were analyzed at both ambient (300 K) and elevated (450 K) temperatures, revealing temperature-dependent characteristics and alternating current conductivity. At 0.75 MHz, the dielectric permittivity (ɛ’) was measured at 31, with tangent loss at 2.01 and a.c. conductivity at 2.597 × 10-3 O−1 m−1. Increasing the frequency to 6.0 MHz resulted in a 2.38-fold rise in dielectric permittivity and a decrease in tangent loss to 0.77, demonstrating the temperature-sensitive nature of dielectric relaxation.