Amorphous Carbon Layer Research Articles

Effect of a-MoS2 and a-MoS3 nanophases on tribological properties of nanocomposite coatings containing diamond-like carbon

Using the modes of reactive and vacuum pulsed laser deposition, nanocomposite coatings consisting of alternating layers of amorphous molybdenum sulfide (a-MoSx) and diamond-like carbon (a-C) were created. For solid lubricating layers, the compositions a-MoS2 and a-MoS3 were chosen. The study of tribological properties was carried out according to the method of sliding a ball on a disk in very different environmental conditions: humid air, dry air at +25 °C and –100 °C. A significant effect of the composition of the a-MoSx phase on the friction and wear of the nanocomposite coatings in humid air and at low temperature has been established. The use of the a-MoS3 polymer-like phase provided better antifriction properties and increased durability of the coatings. In dry air, the coatings with the a-MoS2 nanophase exhibited a lower coefficient of friction than those with a-MoS3 with approximately the same wear resistance between them. The results of the study of tribo-induced changes in coatings by micro-Raman spectroscopy are presented.

Amorphous Carbon Coated Silicon Wafer as Mold Insert for Precision Glass Molding

Press molding of glass is an emerging research area for micro-optics manufacturing. Despite advancements on coating layers of precision molds for glass molding, challenges still exist towards tailoring non-stick coating to provide consistent replication accuracy in thousands of repetitive molding cycles. In this study, atmospheric pressure chemical vapor deposition (APCVD) is introduced to synthesize nanoscale-thickness amorphous carbon layer on the surface of silicon wafer with liquid benzene as the carbon source and silicone rubber as the silicon oxycarbide (SiOC) source. The micro-morphologies of the coating layers under different conditions are obtained and analyzed. In the press molding, the coating exhibits extraordinary physical properties and can remarkably prevent silicon-glass adhesion under elevated temperature. Typical micro-structures, such as micro-pillar and micro-lens arrays on the amorphous carbon coated silicon wafers, are used as mold inserts in precision glass molding to replicate high-precision optical components. The results indicate that this amorphous carbon coated silicon wafer can replicate intricate micro-structures to glass substrates with high-precision dimensions without macroscopic adhesion. This coating technology will protect the mold materials with low adhesion and improve precision glass molding process.

Encapsulation of 2D MoS2 nanosheets into 1D carbon nanobelts as anodes with enhanced lithium/sodium storage properties

1. This unique nanostructure with 2D MoS2 nanosheets nanoconfined into amorphous carbon layers delivered the excellent electrochemical performance. 2. The composite exhibited high reversible specific capacity, good rate capability and stability.

Advanced aqueous sodium-ion capacitors based on Ni0.25Mn0.75O nanoparticles encapsulated in electrospinning carbon nanofibers.

Manganese oxides are promising cathode material candidates with appropriate positive potential windows for low-cost and safe aqueous sodium-ion capacitors (ASICs). However, their low electrical conductivity issue and the lack of advanced binder-free manganese oxide-based electrodes severely restrict their practical capacitance and application in flexible ASICs. Here, Ni0.25Mn0.75O (NMO) nanoparticles uniformly encapsulated in carbon nanofiber films with excellent flexibility are fabricated by electrospinning and subsequent carbonization. The uniformly amorphous carbon layer enhances the conductivity, avoids dissolution and alleviates the volume or stress change of NMO during ion intercalation or mechanical deformation. More importantly, compared with the flexible electrodes prepared by traditional methods, electrospinning materials can be directly used as binder-free electrodes, which can effectively simplify the process and improve the energy density. Finally, a 2.4 V flexible quasi-solid-state ASIC device is integrated, which exhibits a high energy density of 5.95 mWh cm-3, a high power density of 670 mW cm-3 and an outstanding stability of 1000 cycles. This work offers an effective materials engineering strategy for high-performance binder-free NMO-based cathodes and advanced flexible ASICs.

Elaborate interface design of SnS2/SnO2@C/rGO nanocomposite as a high-performance anode for lithium-ion batteries

The practical application of Sn-based anode materials is limited by their low electrical conductivity and large volume expansion during cycling. To overcome these challenges, a novel SnS2/SnO2@C/rGO nanocomposite is synthesized by in-situ H2O2 oxidation of SnS2@C/rGO that is prepared via a hydrothermal reaction using SnCl2, thiourea, L-ascorbic acid and GO as the reactants. Tightly contacted SnS2/SnO2 heterostructured nanoparticles are encapsulated by the amorphous carbon derived from L-ascorbic acid, which are further firmly anchored on the rGO sheets through the chemical interactions between the hydroxyl groups of L-ascorbic acid and hydroxyl/carbonyl groups of rGO. The amorphous carbon layer can act as a spacer to prevent the stacking of rGO sheets to retain the ion transport pathway. Meanwhile, the N and S heteroatoms are co-doped into the rGO sheets by using thiourea as N and S sources, which can enhance the electrical conductivity and provide more active sites for Li+ insertion/extraction. The obtained nanocomposite exhibits a specific capacity of 689 mA h g−1 after 300 cycles at a current density of 0.1 C (1 C = 783 mA g−1) and a moderate capacity of 619 mA h g−1 up to 500 cycles at a large current rate of 0.5 C.

Activating the Extra Redox Couple of Co2+/Co3+ for a Synergistic K/Co Co-Substituted and Carbon Nanotube-Enwrapped Na3V2(PO4)3 Cathode with a Superior Sodium Storage Property.

Na3V2(PO4)3 (NVP) materials have emerged as a promising cathode for sodium ion batteries (SIBs). Herein, NVP is successfully optimized by dual-doping K/Co and enwrapping carbon nanotubes (CNTs) through a sol-gel method. Naturally, the occupation of K and Co in the Na1 sites and V sites can efficiently stabilize the crystal cell and provide the expanded Na+ transport channels. The existence of tubular CNTs could restrict the crystal grain growth and effectively downsize the particle size and provide a shorter pathway for the migration of electrons and ions. Moreover, the amorphous carbon layers combined with the conductive CNTs form a favorable network for the accelerated electronic transportation. Furthermore, the ex situ XPS characterization reveals that an extra redox reaction pair of Co2+/Co3+ is successfully activated at the high voltage range, resulting in superior capacity and energy density property for KC0.05/CNTs composites. Comprehensively, the optimized KC0.05/CNTs electrode exhibits a distinctive electrochemical property. It delivers an initial reversible capacity of 119.4 mA h g-1 at 0.1 C, surpassing the theoretic value for the NVP system (117.6 mA h g-1). Moreover, the KC0.05/CNT electrode exhibits the initial capacity of 113.2 mA h g-1 at 5 C and 105.8 mA h g-1 at 10 C, and the maintained capacities at 500 cycles are 105.8 and 100.8 mA h g-1 with outstanding retention values of 96.6 and 95.3%. Notably, it releases capacities of 99.8 and 84.5 mA h g-1 at 50 and 100 C, and the capacity retention values at 2500 cycles are 66.2 and 58.8 mA h g-1, respectively. What is more, the KC0.05/CNTs//Bi2Se3 asymmetric full cell exhibits a high capacity of 191.4 mA h g-1 at 2.65 V, with the energy density being as high as 507 W h kg-1, demonstrating the eminent practical application potential of KC0.05/CNTs in SIBs.

TEA driven C, N co-doped superfine Fe3O4 nanoparticles for efficient trifunctional electrode materials

Poor conductivity is an obstacle that restricts the development of the electrochemistry performance of Fe3O4. In this work, a novel carbon and nitrogen co-doped ultrafine Fe3O4 nanoparticles (CN-Fe3O4) have been synthesized by triethylamine (TEA) induction and subsequent calcination. The addition of TEA could not only regulate the size of Fe3O4 nanoparticles, but also promote the formation of amorphous carbon layer. Well-designed CN-Fe3O4 heterostructures provide a highly interconnected porous conductive network, large heterogeneous interface area, large specific surface area and a large number of active sites, which greatly improve conductivity and promote electron transfer and electrolyte diffusion. The prepared CN-Fe3O4 electrode exhibits a high specific capacitance of 399.3 mF cm−2 and good cycling stability. Meanwhile, CN-Fe3O4 catalyst exhibits excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities, with overpotentials of 136 and 281 mV at the current density of 10 mA cm−2, respectively. This work provides a promising approach for the design of high-performance anode materials for supercapacitors and provides profound implications for the development of catalysts with bifunctional catalytic activity.

An individual sandwich hybrid nanostructure of cobalt disulfide in-situ grown on N doped carbon layer wrapped on multi-walled carbon nanotubes for high-efficiency lithium sulfur batteries

Binding and trapping of lithium polysulfide (LPS) are being conceived as the most effective strategies to improve lithium-sulfur (Li-S) battery performance. Therefore, exploiting a simple but cost-effective approach for the absorption and conversion of LPS and the transfer of electrons and Li+ ions is of paramount importance. Herein, sandwich structure MWCNTs@N-doped-C@CoS2 integrated with multiple nanostructures of zero-dimensional (0D) CoS2 nanoparticles, 1D carbon nanotubes (CNTs), and 2D N-doped amorphous carbon layer was obtained, where MWCNTs was firstly uniformly attached with a polydopamine (PDA) of excellent adhesion, followed by hydrothermal method, the Co2+ nanoparticles were in-situ grown on the PDA by the formation of complex compound of Co2+ and N atoms in PDA, and then the CoS2 nanoparticles were in-situ grown on CNTs in a point-surface contact way by a bridging of N-doped amorphous carbon layer derived from the carbonization of attached PDA after the vulcanization at 500 °C under Ar atmosphere. The multifunction synergism of absorption, conductivity, and the kinetics of LPS redox is significantly improved, consequently effectively suppressing the shuttle effect and tremendously increasing the utilization rate of active substance. For the Li-S battery assembled with MWCNTs@N-doped-C@CoS2-modified separator, its rate capacity and cycling performance can be greatly enhanced. It can exhibit a high initial discharge capacity of 1590 mAh g−1 at 0.1 C, a stable long-term cycling performance with a relatively low capacity decay of 0.07% per cycle during 500 cycles at 1 C, and a reversible capacity of 772 mAh g−1 and a capacity decay of 0.04% per cycle during 250 cycles at 2 C. Even at a large current density of 4 C, an initial specific discharge capacity of 634 mAh g−1 can still be delivered. With a high sulfur loading of 5.0 mg cm−2, additionally, an outstanding cycling stability can also be well maintained at 685 mAh g−1 at 0.1 C after 50 cycles. This work provides a novel and simple but effective strategy to develop such sandwich hybrid materials comprised of polar metal sulfides and conductive networks via an effective bridging to help realize durable and stable Li-S battery.

Advanced cathode for dual-ion batteries: Waste-to-wealth reuse of spent graphite from lithium-ion batteries

The amount of spent lithium-ion batteries (LIBs) is constantly increasing as their popularity grows. It is important to develop a recycling method that cannot only convert large amounts of waste anode graphite into high value-added products but is also simple and environmentally friendly. In this work, spent graphite from an anode was transformed into a cathode for dual-ion batteries (DIBs) through a two-step treatment. This method enables the crystal structure and morphology of spent graphite to recover from the adverse effects of long cycling and be restored to a regular layered structure with appropriate layer spacing for anion intercalation. In addition, pyrolysis of the solid electrolyte interphase into an amorphous carbon layer prevents the electrode from degrading and improves its cycling performance. The recycled negative graphite has a high reversible capacity of 87 mAh g−1 at 200 ​mA ​g−1, and its rate performance when used as a cathode in DIBs is comparable to that of commercial graphite. This simple recycling idea turns spent anode graphite into a cathode material with attractive potential and superior electrochemical performance, genuinely achieving sustainable energy use. It also provides a new method for recovering exhausted batteries.

A novel strategy for synthesizing the large size Co9S8@C nanosheets as anode for lithium-ion batteries with superior performance

The cobalt sulfides have become the focus materials on the lithium ion batteries application in which the Co9S8 with the nanosheet structure is the promising candidate for anode material in high-energy and high-power lithium ion batteries. By introducing a novel strategy with the organic-inorganic hybrid Co9S8-DETA (DETA=Diethylenetriamine) as the precursor, the large size Co9S8@C nanosheets have been successfully prepared via a calcination process. Due to uniform two-dimensional structure of Co9S8 and the amorphous carbon layer coating, the as-prepared Co9S8@C nanosheets exhibited excellent lithium ion storage performance as an anode material. The reversible capacity could be retained at 595 mAh g−1 after 160 cycles at 0.2 A g−1. The excellent performances of this nanocomposite offer numerous opportunities for other sulfides as a new anode in lithium ion batteries.

Oxygen-etchant-promoted synthesis of vertically aligned graphene arrays in a Joule heater and defogger

Vertically aligned graphene arrays (VAGAs), as a vertical ordering generated via the accumulation of longitudinally grown two-dimensional graphene with excellent porosity and large specific surface area, were suggested as candidates for application in thermal management. However, when using the current strategy of preparing VAGAs, amorphous carbon layers appear as interfacial layers, diminishing the performance of such VAGAs-based devices. Herein, the direct approach of superb thermal conductivity, super-hydrophobicity, and the use of low-resistance VAGAs on glass is reported using the combination of UV/ozone treatment and in-situ plasma-enhanced chemical vapor deposition (PECVD). The use of a UV/ozone-etchant can reduce the amorphous carbon species on the target substrate and promote VAGAs nucleation. The growth mechanism therein is investigated and elucidated. Direct synthesis of VAGAs on glass can combine the complementary features of traditional glass and modern materials. Based on the superb vertical thermal/electrical conductivity, VAGAs on functional glass, thus formed with VAGA/glass and can act as a heater and defogger, the benefits of this VAGA defogger lie in its ultrafast defogging time for relatively low input voltages and unique defogging stability, reaching a saturation temperature of up to 160 °C when 25 V was applied for 16 s. Our study is conducive to investigation of the direct synthesis of VAGAs on glass and its potential importance in thermal management.

Investigation of Structure Modification of Underlying SiCOH Low-kDielectrics with Subsequent Hardmask Deposition Process Conditions

Device miniaturization requires the use of hardmasks in the IC manufacturing process, and employing an amorphous carbon layer (ACL) hardmask over a low-kdielectric is a well-known technology. An elevated temperature causes a dielectric constant shift owing to structural changes and methyl group desorption in the deposited SiCOH films. In this study, the structural change of the SiCOH film, which varies depending on the ACL deposition condition, was analyzed. Structural changes in SiCOH after ACL deposition were analyzed using Fourier transform infrared spectroscopy (FTIR). From 900 to 1300 cm−1wavenumber, changes of methyl group and structure of the SiCOH film were identified. As a result, we found that the structure and methyl content of the low-kfilm changes during the hardmask deposition due to the heat and plasma. In particular, the SiCOH film is richer in methyl group at higher temperatures. A high-density hardmask was deposited at higher temperatures. It was deduced that a high-density ACL hardmask was deposited on SiCOH because of the higher temperature, and the ACL hardmask on low-kacts as a capping layer.

Kinetic Mechanism of Reactive Oxygen/Nitrogen Species in Plasma-Assisted Greenhouse Gas Replacement

In semiconductor manufacturing, greenhouse gases, such as perfluorocarbons (PFCs) and nitrogen trifluoride (NF3), which are sources of global warming, are frequently used to remove substances during cleaning and etching. Particularly, NF3, which has a high global warming potential (GWP) is widely used for chamber cleaning in the chemical vapor deposition (CVD) process. There is an urgent need to replace high GWP gases with eco-friendly gases. In this study, we investigated the possibility of replacing NF3 with N2 gas from the existing NF3/O2 gas mixture during the cleaning process in a plasma-enhanced CVD (PECVD) chamber for the formation of an amorphous carbon layer. The kinetic reaction mechanism of nitrogen-augmented plasma was investigated using ANSYS Chemkin-Pro, and the verification was conducted using an environmentally friendly gas-based direct plasma cleaning process in the PECVD chamber with capacitively coupled plasma (CCP). The verification experiment was conducted with a 150-mm laboratory scale and a 300-mm production equipment. Chemical reaction analysis was then performed to analyze the chemical reaction mechanism in the plasma and identify the trends in the cleaning efficiency. The results derived from the analytical and empirical experiments showed that the addition of N2 positively affected the reaction of O2 in the plasma with surface materials; this improved the cleaning, and the effectiveness of eco-friendly cleaning processes using alternative gases could be confirmed.

High-Performance Amorphous Carbon Coated LiNi0.6Mn0.2Co0.2O2 Cathode Material with Improved Capacity Retention for Lithium-Ion Batteries

Coating conducting polymers onto active cathode materials has been proven to mitigate issues at high current densities stemming from the limited conducting abilities of the metal-oxides. In the present study, a carbon coating was applied onto nickel-rich NMC622 via polymerisation of furfuryl alcohol, followed by calcination, for the first time. The formation of a uniform amorphous carbon layer was observed with scanning- and transmission-electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS). The stability of the coated active material was confirmed and the electrochemical behaviour as well as the cycling stability was evaluated. The impact of the heat treatment on the electrochemical performance was studied systematically and was shown to improve cycling and high current performance alike. In-depth investigations of polymer coated samples show that the improved performance can be correlated with the calcination temperatures. In particular, a heat treatment at 400 °C leads to enhanced reversibility and capacity retention even after 400 cycles. At 10C, the discharge capacity for carbon coated NMC increases by nearly 50% compared to uncoated samples. This study clearly shows for the first time the synergetic effects of a furfuryl polymer coating and subsequent calcination leading to improved electrochemical performance of nickel-rich NMC622.

Preparation and characterization of nanodiamond reinforced aluminum matrix composites by hot-press sintering

In the present paper, aluminum matrix composites (AMCs) reinforced by nanodiamond (ND) were fabricated by hot-press sintering. The morphology and microstructure of ND/Al composite powders for different milling hours were observed. The effect of ND content on microstructure, mechanical properties and tribological behavior of AMCs was investigated. The relative density, hardness, compressive strength and wear resistance of AMCs with different ND contents were compared. The flake-shape aluminum particles with uniformly distributed ND particles were formed by ball milling for 15 h. A laminated structure of AMCs was formed by hot-press sintering at 550 °C for 5 min. ND was distributed at the grain boundary of Al matrix. At the interface between Al and ND, a layer of Al with high dislocation density was formed, which was closely connected with a layer of amorphous carbon. With increasing of ND content, more and larger pores were presented in AMCs, which caused a decrease in relative density. The hardness, compressive strength and wear resistance of AMCs were significantly improved in comparison with sintered aluminum. The AMC with 2.5% ND obtained the highest hardness and compressive strength and the lowest coefficient of friction and wear rate.

Morphology and Growth Region Analysis of Carbon Nanotubes Growth in Water-Assisted Flame Synthesis

ABSTRACT Water has been proven to be an effective additive to enhance the growth rate and purity of the synthesized carbon nanotubes (CNTs) in the chemical vapor deposition (CVD) method. Due to similar CNT growth parameters in CVD and flame environment, it is expected that a similar effect can be replicated in CNT flame synthesis to a certain degree. The present study analyzes the effect of water addition to the fuel stream toward the CNT growth in methane diffusion flame under atmospheric conditions. Water vapor was introduced into the fuel gas by passing the methane gas through a water bubbler, and the growth condition was analyzed based on a cross-sectional analysis of the grown CNT on top of nickel wire. The water addition to the fuel reduces the axial extent of the growth region due to the reduction in flame height. Even though the spatial distribution of the growth region in the flame with water additive changes compared to that of the flame without water, the average growth region temperature is relatively identical for both flames at a similar height above the burner. The synthesized CNT morphology did not change with the addition of water due to similar temperatures within the growth region and inhomogeneity of catalyst nanoparticle formation. Remarkably, the thickness of the amorphous carbon layer in the growth region decreases by almost 20% in water-assisted flame due to the reduction of carbon supply caused by the modification of gas-phase chemical reaction and water vapor etching effects that happen within the growth region. Numerical simulation of the flame structure shows that addition of water vapor in the fuel stream lowers the methane concentration within the CNT growth region and simultaneously promotes water etching effects on the amorphous carbon layer.

Self-assembled homogeneous SiOC@C/graphene with three-dimensional lamellar structure enabling improved capacity and rate performances for lithium ion storage

SiOC as an alternative silicon-based material possesses great potential in lithium ion batteries due to its high reversible capacity, tunable chemical component and various synthetic route. However, large-scale production of SiOC powders grinded from SiOC bulks is restricted in commercial application because of the poor electrical conductivity. Herein, three dimensional (3D) lamellar SiOC@C/rGO composite is fabricated through hydrothermal reaction and electrostatic self-assembly process, in which SiOC powders encapsulated by amorphous carbon layers are homogeneously dispersed in graphene sheets. Cfree nanoclusters in SiOC, carbon layers on SiOC surface and graphene supporters in the composite establish the multidimensional interconnected conductive architecture and possess favorable interfacial adhesion. Therefore, SiOC@C/rGO exhibits high specific capacity (676 mAh g−1 at 200 mA g−1) and remarkable rate capability (306.4 mAh g−1 at 4000 mA g−1). The full cell assembled with this anode and LiFePO4 cathode also demonstrates stable voltage platform and good performance for 200 cycles. The excellent performance of SiOC@C/rGO profits from the synergistic effect of robust construction, multidimensional conductive architecture and chemical. CompositionThe proposed strategy can also be developed to prepare other materials with graphene layer to enhance their electrical conductivity for commercial application.

High-capacity, low-tortuosity LiFePO4-Based composite cathode enabled by self-supporting structure combined with laser drilling technology

A thick electrode with high areal capacity is a promising way to improve the energy density of batteries, but the development of a thick electrode is limited by poor mechanical stability and sluggish ion and electron transport. Here, we design a self-supporting cathode that consists of cellulose nanofibers, multi-walled carbon nanotubes, and lithium iron phosphate (LFP), and introduce a uniform microchannel structure to the cathode by laser drilling technology. The cellulose nanofibers and multi-walled carbon nanotubes construct a conductive network. The microchannel structure enables outstanding ion and electron transport and significantly improves the rate capability of the electrode. Meanwhile, the local heat by the laser produces an amorphous carbon layer on the inner surface of the microchannel, which helps form a stable cathode-electrolyte interface and enhances the capacity retention of the thick electrode. Notably, the drilled thick cathode with an LFP load of 40 mg cm−2 and an areal capacity of 5.33 mAh cm−2 exhibits substantially improved cycling stability at 0.5C than the undrilled samples. This work demonstrates a promising design concept for thick electrodes to high-performance energy storage devices.

In-situ synthesis of aluminum matrix nanocomposites by selective laser melting of carbon nanotubes modified Al-Mg-Sc-Zr alloys

Aluminum matrix nanocomposites were manufactured by selective laser melting (SLM) of 0.5 wt% multi-walled carbon nanotubes (MWCNTs) modified Al-Mg-Sc-Zr alloys. The influence of MWCNT addition on the manufacturing quality, the phase formation and the mechanical properties of the Al-Mg-Sc-Zr alloys was investigated. It is found that primary Al3(Sc,Zr) particles precipitated and were uniformly dispersed in both equiaxed and columnar regions of the SLM-fabricated MWCNTs/Al-Mg-Sc-Zr nanocomposites. New Al4C3 phase was generated either on the open tip or in the defected and amorphous carbon layer of the MWCNTs, covering their overall surface. The unreacted MWCNTs completely transferred to Al4C3 upon heat treatment, forming a stable {003} Al4C3/{200}Al interface. The heat-treated MWCNTs/Al-Mg-Sc-Zr nanocomposites exhibit high microhardness of 169.0 ± 0.7 HV0.2, tensile strength of 544.2 ± 6.8 MPa, yield strength of 505.1 ± 6.3 MPa and elastic modulus of 97.8 ± 0.7 GPa, increasing by 6.3%, 4.5%, 5.0% and 5.6%, respectively, compared with the unmodified Al-Mg-Sc-Zr alloys. The improved performance was ascribed to the collective effects of precipitation strengthening of secondary Al3(Sc,Zr) nanoparticles, in-situ synthesis of Al4C3 as well as favorable interfacial bonding for effective load transfer. This study can provide reference values for laser additive manufacturing of MWCNTs modified other metallic alloys to enhance their comprehensive properties.

Designing flexible asymmetric supercapacitor with high energy density by electrode engineering and charge matching mechanism

Extensive exploratory works are dedicating to increase the energy density of aqueous asymmetric supercapacitors (AASCs), from the perspective of augmenting the specific capacitance and widening the operating voltage window. Herein, Mxene (V2C) derived unique accordion-like layered vanadium nitride coated by ultrathin amorphous carbon layer (L-VN@AC) is synthesized via a facile nitride strategy as negative electrode materials for AASC. Profiting from the distinctive layered structure inherited from V2C, the resultant L-VN@AC electrode exhibits a more remarkable areal capacitance (631.4 mF cm−2) and outstanding rate capability compared to the V2C precursor and commercial vanadium nitride (C-VN). Furthermore, a brand-new charge matching mechanism is proposed for the assembly of AASCs with capacitive-type (pseudocapacitance/electric double layer capacitance) electrode materials to soften the impact of energy density ascribed to the capacitance gap between the asymmetrical electrodes. Based on this charge matching mechanism, an optimized L-VN@AC//α-MnO2 AASC with 2.4 V operating voltage is assembled to achieve the enhancements in energy densities (597.5 μWh cm−2 at 2.4 mW cm−2 and 8.5 mWh cm−3 at 34.3 mW cm−3). It is believed that the design of high-performance L-VN@AC electrode materials and the proposal of balanced capacitance mechanism will provide new insights for the development of supercapacitors from two aspects of material synthesis and device assembly mechanism.