Ultrathin Electrode Research Articles

Spray-Coated Ultrathin and Porous Films for Physiological Sensing and Force Detection.

Epidermal electronics employed on human skin for the long term require good breathability and nonforeign wearing. In this work, we combine phase separation and spray coating to fabricate a porous and ultrathin electrode within minutes as well as micrometer-scale porous pressure sensors. The resulting electrodes show a water vapor transmission rate of 18.4 mg·cm-2·h-1, sheet resistance of 5.2 Ω/sq, and thickness below 5 μm. The introduction of the biogel further reduced the electrode-skin impedance, which is lower than that of the commercial gel electrode, indicating that the electrode can have a high degree of conformal contact with the skin. The epidermal electronics prepared by this strategy exhibit an excellent performance in force sensing. Such results strongly prove the efficiency and practicality of the strategy.

Mitigating interfacial recombination enabling efficient semitransparent organic photovoltaics

Charge recombination at the interface between top electrode and active layer is a substantial current loss pathway in semitransparent organic photovoltaics (STOPVs). Reducing interfacial traps is an effective strategy to mitigate interfacial recombination and promote charge extraction, and thereby improve the power conversion efficiencies (PCEs). Herein, a facile approach of depositing 11-mercapto-undecanoic acid (11-MUA) on zinc oxide (ZnO) cathode interlayer in conventional STOPVs is demonstrated. 11-MUA can form covalent interactions with both ZnO and silver (Ag) and thus can induce the formation of high-quality ultrathin Ag electrode. Compared with that deposited on bare ZnO, the Ag electrode on ZnO/11-MUA shows higher conductivity as well as higher optical transparency. The STOPVs based on ZnO/11-MUA/Ag exhibit 2 orders of magnitude lower surface trap density than the counterparts based on ZnO/Ag. Consequently, 11-MUA simultaneously improves the PCEs from 11.2% to 12.1% and average visible transmittance from 21.6% to 27.0% in the STOPVs. Furthermore, arising from the 11-MUA-modified interface, the thermal stability of STOPVs based on ZnO/11-MUA/Ag is also improved.

Lithiophilic Protective Dual Layer Enabling Stable Electrodeposition of Lithium at High Current Density

Lithium (Li) is an ideal anode material for rechargeable batteries and thus manufacturing Li metal is crucial for the practical development of Li metal batteries. Electrodeposition is an efficient technique for producing ultrathin and scalable Li metal electrodes. However, the dendritic growth and the side reactions of Li with electrolyte during the electrodeposition are the main obstacles to overcome. In this study, we designed a pre-coated protective dual layer (PDL) composed of a poly(ethylene oxide)-based solid polymer electrolyte (SPE) and a polydopamine-coated cellulose membrane (PD-CM). The adhesive and ion-conductive SPE layer suppressed the growth of Li dendrites and side reactions with liquid electrolyte. The PD-CM layer with high porosity and lithiophilicity promoted a facile and uniform Li-ion flux. By applying the pre-coated PDL, Li was uniformly electrodeposited on the Ag-coated Cu at a high current density of 6 mA cm−2. The Li/LiFePO4 cell composed of an electrodeposited Li anode with PDL and a LiFePO4 cathode was assembled without an additional separator, and its cycling performance was evaluated. The cell initially delivered a high discharge capacity of 154.8 mAh g−1 at 45 °C and exhibited excellent cycling stability with a capacity retention of 97.0% after 200 cycles.

Next‐Generation Ultrathin Lightweight Electrode for pH‐Universal Aqueous Flow Batteries

AbstractAqueous flow batteries (AFBs) are promising long‐duration energy storage system owing to intrinsic safety, inherent scalability, and ultralong cycle life. However, due to the thicker (3–5 mm) and heavier (300–600 g m−2) nature, the current used graphite felt (GF) electrodes still limit the volume/weight power density of AFBs. Herein, a lightweight (≈50 g m−2) and ultrathin (≈0.3 mm) carbon microtube electrode (CME) is proposed derived from a scalable one‐step carbonization of commercial cotton cloth. The unique loose woven structure composed of carbon microtube endows CME with excellent conductivity, abundant active sites, and enhanced electrolyte transport performance, thereby significantly reducing polarization in working AFBs. As a consequence, CME demonstrates excellent cycling performance in pH‐universal AFBs, including acidic vanadium flow battery (maximum power density of 632.2 mW cm−2), neutral Zn‐I2 flow battery (750 cycles with average Coulombic efficiency of 99.6%), and alkaline Zn‐Fe flow battery (energy efficiency over 70% at 200 mA cm−2). More importantly, the estimated price of CME is only 5% of GF (≈3 vs ≈60 $ m−2). Therefore, it is reasonably anticipated that the lightweight and ultrathin CME may emerge as the next generation electrode for AFBs.

One-step rapid prototyping of recyclable ultrathin CNF/MWCNT/Fe-based spinel oxide asymmetric interdigital nanopaper electrodes for high performance flexible supercapacitors

Flexible asymmetric supercapacitors (FASCs) are potential energy storage devices for wearable electronics, considering that these have a wide operating voltage window, high specific capacity, and high energy density. However, achieving high energy density through the optimization of structure and electrode remains a challenge. Herein, two electrode inks with exceptional homogeneity nature and stability are prepared by using in-situ grown Fe-based spinel oxide (MFe2O4 = Fe3O4/MnFe2O4) on multi-walled carbon nanotubes (MWCNT) combined with eco-friendly and renewable cellulose nanofiber (CNF). Meanwhile, ultrathin flexible asymmetric interdigital nanopaper electrodes (NFT@MnFe and NFT@Fe) with customized patterns are fabricated through a one-step mask-assisted vacuum filtration strategy by using the obtained electrode inks. The planar interdigital FASC device based on the NFT@MnFe cathode and the NFT@Fe anode has excellent area specific capacity (309.8 mF cm−2), energy density (110.2 μW h cm−2), and power density (0.47 mW cm−2). The FASC maintain over 95 % of the original capacity after 5000 charge/discharge cycles. Noteworthy, a stacked interdigital FASC can be achieved with an energy density of up to 273.8 μW h cm−2 at 0.47 mW cm−2 power density, combining the structural benefits of planar interdigital and sandwich-type devices.

Seat to beat: Novel capacitive ECG integration for in-car cardiovascular measurement

Cardiovascular diseases (CVD) are a leading cause of global mortality, responsible for approximately one in five deaths. In response to these concerning statistics, there is a growing need for innovative solutions enabling cardiac monitoring beyond medical facilities. This paper demonstrates the fabrication and development of a novel system designed to be integrated into passenger car seats, facilitating continuous monitoring of passengers’ cardiac activity. The system comprises a capacitive electrode prototype, a custom-designed analog signal processing circuit, and a computing unit. Two ultrathin capacitive electrodes were fabricated with a diameter of 56.42 mm protected by a guard layer to reduce noise. The amplification circuitry was comprised of operational amplifiers tasked with filtering and conditioning the electrocardiogram (ECG) signal. Heart rates calculated from our measurements were comparable with clinical ECG. The experimental setup underwent testing on human subjects while they were in a state of tranquil sitting within passenger cars and also in laboratory conditions. The proposed system offers the flexibility for single and dual power supplies in full capacitive or hybrid mode. Our experimental results confirm the system’s feasibility and its capability to record high-quality signals from weak biopotentials, highlighting its potential for real-world applications.

Ultrathin Protection Layer via Rapid Sputtering Strategy for Stable Aqueous Zinc Ion Batteries

AbstractSurface side reactions and time‐consuming modification methods hinder the practical application of zinc‐ion batteries. This study introduces an ultrathin protection layer for the Zn anode via a rapid sputtering method. The dopants on the CN10@Zn anode create surface dipoles and local variations in charge distribution, facilitating zinc ion migration to pyrrolic nitrogen dopant sites with reduced adsorption barriers. Additionally, hydroxyl oxygen dopants enhance the hydrophilicity of the sputtering layer, forming a strong adhesion with the zinc anode and improving ion accessibility. This results in dense nucleation sites for uniform zinc deposition. Consequently, the sputtered layer achieves a Coulombic efficiency of 99.8% over 2,700 cycles in Cu||Zn cells and a lifespan of up to 2,100 h in zinc symmetric cells. When paired with Na0.65Mn2O4 cathodes, the sputtered layer retains 89% capacity over 1,000 cycles at 1 A g−1. This study presents a promising method for rapidly fabricating ultrathin electrode materials.

Ultrathin Zn(002) textured zinc anodes for dendrite-free and hydrogen evolution-inhibited zinc batteries

For practical rechargeable aqueous zinc-ion batteries, the long-term cycling stability of the zinc anode remains significantly constrained by its low utilization efficiency and the persistent challenge of hydrogen evolution. This study demonstrates the fabrication of ultrathin zinc electrodes with a robust Zn (002) texture while ensuring an adequate supply of zinc metal for use as an anode material. This approach effectively suppresses the tendency of zinc atoms to undergo deposition transformation due to dislocation-induced phenomena. Compared to zinc foils with higher deposition amount, the ultrathin Zn anode exhibits enhanced resistance to dendrite growth and interfacial side reactions. Assembled symmetrical cells based on this ultra-thin Zn anode show a cycle life of 1750 h (1 mAcm−2, 0.5 mAhcm−2), maintaining stable cycling for over 100h even at a high depth of discharge (DOD) of 46.23%. Additionally, the full cell couple with V10O24 exhibits a high initial capacity of 429.6 mAh g−1 and a capacity retention of 75.8% after 1000 cycles.

Resistive switching suppression in metal/Nb:SrTiO3 Schottky contacts prepared by room-temperature pulsed laser deposition

Deepening the understanding of interface-type resistive switching (RS) in metal/oxide heterojunctions is a key step for the development of high-performance memristors and Schottky rectifiers. In this study, we address the role of metallization technique by fabricating prototypical metal/Nb-doped SrTiO3 (M/NSTO) Schottky contacts via pulsed laser deposition (PLD). Ultrathin Pt and Au electrodes are deposited by PLD onto single-crystal (001)-terminated NSTO substrates and interfacial transport is characterized by conventional macroscale methods and nanoscale Ballistic Electron Emission Microscopy. We show that PLD metallization gives Schottky contacts with highly reversible current-voltage characteristics under cyclic polarization. Room-temperature (RT) transport is governed by thermionic emission with Schottky barrier height ϕB(Pt/NSTO)∼0.71−0.75eV , ϕB(Au/NSTO)∼0.70−0.83eV and ideality factors as small as n(Pt/NSTO)∼1.1 and n(Au/NSTO)∼1.6 . RS remains almost completely suppressed upon imposing broad variations of the Nb doping and of the external stimuli (polarization bias, working temperature, ambient air exposure). At the nanoscale, we find that both systems display high spatial homogeneity of ϕB ( ⩽50meV ), which is only partially affected by the NSTO mixed termination ( |ϕB(M/SrO)−ϕB(M/TiO2)|<35meV ). Experimental evidences and theoretical arguments—based on a metal-insulator-semiconductor description of the M/NSTO—indicate that the PLD metallization mitigates interfacial layer effects responsible for RS. This occurs thanks to the reduction of the interfacial layer thickness and to the creation of an effective barrier against the permeation of ambient gas species affecting charge trapping and redox reactions. This description allows to rationalize interfacial aging effects, observed upon several-months-exposure to ambient air, in terms of a slow interfacial re-oxidation. Our work contributes to the fundamental understanding of interface-type RS and demonstrates that RT PLD offers a viable platform for the realization of robust, RS-free NSTO-based Schottky contacts.

Preparation and Performance Evaluation of Microporous Transport Layers for Proton Exchange Membrane (PEM) Water Electrolyzer Anodes

In this work, ≈25 μm thin titanium microporous layers (MPLs) with ≈2 μm small pores and low surface roughness were coated and sintered on top of ≈260 μm thick commercial titanium-powder-sinter sheets with ≈16 μm pores, maintaining a porosity of ≈40% in both layers. Serving as porous transport layers (PTLs) on the anode side in proton exchange membrane water electrolyzers (PEMWEs), these pore-graded, two-layer sheets (“PTL/MPL”) are compared to single-layer PTLs in single-cell PEMWEs. The PTL/MPL samples prepared here give a 3–6 mΩ cm2 lower high-frequency resistance (HFR) compared to the as-received single-layer PTL, which is attributed to a partial reduction of the TiO2 surface passivation layer during the MPL sintering process. For ≈1 μm thin anodes with an iridium loading of ≈0.2 mgIr cm−2, the use of an MPL leads to a ≈24 mV improvement in HFR-free cell voltage at 6 A cm−2. As no such benefit is observed for ≈9 μm thick anodes with ≈2.0 mgIr cm−2, mass transport resistances within the PTL/MPL play a minor role. Possible reasons for the higher catalyst utilization in ultra-thin electrodes when using an MPL are discussed. Furthermore, an MPL provides superior mechanical membrane support, which is particularly relevant for thin membranes.

Enhanced contact resistance reduction in MoS2 transistors via ultrathin LiPON electrode interface doping

Two-dimensional (2D) semiconductors are considered one of the most promising channel materials in devices for the future development of integrated circuits with low power consumption and high integration. As the size of the device gradually decreases, a key challenge is to reduce the contact resistance of nanoscale devices. Doping is a crucial strategy to realize low contact resistances in 2D devices, but there is still lack of simple and compatible doping methods. Here, we report a simple and localized doping strategy that adopts an ultrathin lithium phosphorus oxynitride (LiPON) as the buffer layer of electrodes to reduce the contact resistance of MoS2 transistors. This ultrathin buffer layer induces strong n-doping in the electrode contact area, thereby achieving nearly Ohmic contact in the devices. The contact resistances of LiPON/Ti/Au electrodes for different channel carrier densities are all lower than those of Ti/Au electrodes because the Schottky barrier height (SBH) for the LiPON/Ti/Au electrodes is only 8% of the value for the Ti/Au electrodes. This work provides a simple and compatible strategy for the development of high-performance 2D devices and deepens the understanding of the important role of doping in 2D electrical contacts.

Ultrathin Electrode of Binder Free Energy Storage Device: Fabrication of MgO@RGO Nanocomposites through Hierarchical Synthesis

Ultrathin Electrode of Binder Free Energy Storage Device: Fabrication of MgO@RGO Nanocomposites through Hierarchical Synthesis

Ultrathin skin-conformable electrodes with high water vapor permeability and stretchability characteristics composed of single-walled carbon nanotube networks assembled on elastomeric films

Herein, we report on conductive ultrathin films (nanosheets) with the characteristics of stretchability and water vapor permeability for skin-conformable bioelectrodes. The films are fabricated by combining conductive fibrous networks of single-wall carbon nanotubes (SWCNTs) and poly(styrene-b-butadiene-b-styrene) (SBS) nanosheets (i.e., SWCNT-SBS nanosheets). An increase in the number of SWCNT coatings increases both the thicknesses and densities of the SWCNT bundles. The SBS nanosheets coated with three layers of SWCNTs (i.e., SWCNT 3rd-SBS nanosheets) show comparable sheet resistance to the SBS nanosheets coated with poly(3,4-ethylenedioxithiophene) doped with poly(4-styrenesulfonate acid) (PEDOT:PSS) containing 5 wt.% butylene glycol (i.e., PEDOT:PSS/BG5-SBS nanosheets). In addition, the SWCNT 3rd-SBS nanosheets exhibit significantly reduced elastic moduli and increased elongations at break compared to the PEDOT:PSS/BG5-SBS nanosheets. Furthermore, the calculated water vapor transmission ratio of the 210-nm-thick SBS nanosheets (268,172 g m−2 (2 h)−1) is greater than that of the filter paper (6345 g m−2 (2 h)−1). The SWCNT 3rd-SBS nanosheets attached to model skin show high tolerances to bending and artificial sweat at different pH values (i.e., the electrical resistance changes ~1.1 times). Finally, the SWCNT 3rd-SBS nanosheet is applied to detect the surface electromyogram from the forearm of a subject. This nanosheet displays a signal-to-noise ratio similar to that of the PEDOT:PSS/BG5-SBS nanosheet.

All-in-one, gas-permeable, ultrathin, flexible, and self-adhesive epidermal electrode for biopotential recording and muscle theranostics

Epidermal electronics have attracted extensive attention owing to their potential in personal healthcare and human–machine interactions (HMIs). However, their low conductivity and poor ability to conform to the human skin impede their practical application. Herein, a multifunctional flexible dry epidermal electrode for biopotential recording and muscle thermotherapy was developed based a conductive polymer (poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonic acid (PEDOT:PSS)). PEDOT:PSS was modified using poly(vinyl alcohol) (PVA) with hydrophobic groups. The electrode is able to self-adhere to human skin through a hydrophobic interaction with the skin. Moreover, the hydrophilic groups can absorb the humidity under the skin and move it by the hydrophobic groups, which allows the electrode exhibits good gas-permeability. The ultrathin electrode conforms well to the topography of the human skin and, thus, can form a stable and intimate interface with it, resulting in a low electrode–skin contact impedance that allows the recording of biopotentials with high quality. Moreover, the electrode exhibits rapid Joule heating performance at a low voltage (up to 53.8 °C in 12 s at 1.5 V), which is suitable for the electrothermal therapy of muscle. On-body measurements confirm that our electrode could detect muscle fatigue via electromyography (EMG) and perform electrothermal therapy to relieve muscle fatigue. This study offers an efficient method for developing all-in-one wearable flexible epidermal electrode for biopotential recording and muscle theranostics.

Single-crystalline hole-transporting layers for efficient and stable organic light-emitting devices

Efficient charge-carrier injection and transport in organic light-emitting devices (OLEDs) are essential to simultaneously achieving their high efficiency and long-term stability. However, the charge-transporting layers (CTLs) deposited by various vapor or solution processes are usually in amorphous forms, and their low charge-carrier mobilities, defect-induced high trap densities and inhomogeneous thickness with rough surface morphologies have been obstacles towards high-performance devices. Here, organic single-crystalline (SC) films were employed as the hole-transporting layers (HTLs) instead of the conventional amorphous films to fabricate highly efficient and stable OLEDs. The high-mobility and ultrasmooth morphology of the SC-HTLs facilitate superior interfacial characteristics of both HTL/electrode and HTL/emissive layer interfaces, resulting in a high Haacke’s figure of merit (FoM) of the ultrathin top electrode and low series-resistance joule-heat loss ratio of the SC-OLEDs. Moreover, the thick and compact SC-HTL can function as a barrier layer against moisture and oxygen permeation. As a result, the SC-OLEDs show much improved efficiency and stability compared to the OLEDs based on amorphous or polycrystalline HTLs, suggesting a new strategy to developing advanced OLEDs with high efficiency and high stability.

Centrifugal-Gravity-Enforced Deposition of MXene Electrodes for High-Performance and Ultrastable Microsupercapacitors.

Two-dimensional (2D) transition metal carbides, known as MXenes, have captured much attention for their excellent electrical conductivity and electrochemical capability. However, the susceptibility of MXenes to oxidation, particularly Ti3C2Tx transforming into titanium dioxide upon exposure to ambient air, hinders their utilization for extended operational life cycles. This work introduces a simple and straightforward method for producing ultrathin MXene electrode films tailored for energy storage applications, employing centrifugal-gravity force. Our approach significantly suppresses the oxidation phenomenon that arises in MXene materials and also effectively prevents the recrystallization of potentially residual LiF during the film formation. Additionally, the utilization of this MXene electrode in an all-solid-state microsupercapacitor (MSC) with an interdigitated pattern demonstrates an exceptionally improved and stable electrochemical performance. This includes a high volumetric capacitance of approximately 467 F cm-3, an energy density of around 65 mWh cm-3, and impressive long-term cycle stability, retaining about 94% capacity after 10 000 cycles. Moreover, a downsized MSC device exhibits remarkable mechanical durability, retaining over 98% capacity even when folded and sustaining stability over extended periods. Therefore, we believe that this study provides valuable insights for advancing highly integrated energy storage devices, ensuring exceptional electrochemical efficiency and prolonged functionality in diverse environments, whether ambient or humid.

A combination of logical judging circuit and water-resistant ultrathin film PEDOT: PSS electrode for noninvasive ECG measurement

Heart disease-related deaths have increased in recent decades, with most patients dying of sudden cardiac arrest. In such instances, the effect of regular electrocardiogram (ECG) measurements is minimal. Therefore, long-term ECG monitoring has become increasingly important. In this paper, we report a non-adhesive high accuracy ECG monitoring system that can be used in various scenarios without interfering with daily activities. The ECG ultra-thin film electrode is made by water-resistant material based on poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) (PEDOT: PSS) electrode doped with ethylene glycol (EG) and xylitol, to improve the noise signal caused by sweat. The optimal ratio of the three ingredients of PEDOT: PSS/xylitol/EG was determined experimentally to accommodate the ECG monitoring. By using the proposed selectively closed multi-channel single-lead logic circuit, the noise of ECG signal received from the proposed film electrode can be successfully reduced during broad-area electrode measurements, thus to improve ECG measurement accuracy.

Polymeric Conductive Adhesive-Based Ultrathin Epidermal Electrodes for Long-Term Monitoring of Electrophysiological Signals.

Electrophysiology, exploring vital electrical phenomena in living organisms, anticipates broader integration into daily life through wearable devices and epidermal electrodes. However, addressing the challenges of the electrode durability and motion artifacts is essential to enable continuous and long-term biopotential signal monitoring, presenting a hurdle for its seamless implementation in daily life. To address these challenges, an ultrathin polymeric conductive adhesive,poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)/polyvinyl alcohol/d-sorbitol (PPd) electrode with enhanced adhesion, stretchability, and skin conformability, is presented. The skin conformability and stability of electrodes is designed by theoretical criteria obtained by mechanical analysis.Thus, impedance stability is obtained over 1-week of daily life, and the PPd electrode addresses the challenges related to durability during prolonged usage. Proving stability in electromyography (EMG) signals during high-intensity exercise, the wireless PPd measurement system exhibits high signal-to-noise ratio (SNR) signals even in situations involving significant and repetitive skin deformation. Throughout continuous 1 week-long electrocardiogram (ECG) monitoring in daily life, the system consistently preserves signal quality, underscoring the heightened durability and applicability of the PPd measurement system.

Tri-system integration in metal-oxide nanocomposites via in-situ solution-processed method for ultrathin flexible transparent electrodes

For stable operation of ultrathin flexible transparent electrodes (uFTEs), it is critical to implement effective risk management during concurrent multi-loading operation of electrical bias and mechanical folding cycles in high-humidity environments. Despite extensive efforts in preparing solution-processed uFTEs with cost-effective and high-throughput means, achieving in-situ nano-adhesion in heterogeneous metal-oxide nanocomposites remains challenging. In this work, we observed by serendipity liquid-like behaviour of transparent metal-oxide-semiconductor zinc oxide nanoparticles (ZnONPs) onto silver nanowires (AgNWs) developed by in-situ solution processed method (iSPM). This enabled us to address the long-standing issue of vulnerability in the nanocomposite caused by the interface of dissimilar materials between AgNWs and ZnONPs, resulting in a remarkably improved multi-loading operation. Importantly, substrate-integrated uFTEs constituted of the metal-oxide nanocomposite electrode semi-embedded in the polymer matrix of greatly thin <0.5 μm thickness is successfully demonstrated with the smooth surface topography, promoted by the tri-system integration including (i) AgNW-AgNW, (ii) ZnONP-ZnONP, and (iii) AgNW-ZnONP systems. Our finding unveils the complex interfacial dynamics associated with the heterogeneous interface system between AgNWs and ZnONPs and holds great promise in understanding the in-situ nano-adhesion process and increasing the design flexibility of next generation solution-processed uFTEs.

3D Stackable Vertical‐Sensing Electrochemical Random‐Access Memory Using Ion‐Permeable WS2 Electrode for High‐Density Neuromorphic Systems

AbstractIon‐based electrochemical random‐access memory (ECRAM) is proposed for synaptic applications owing to its promising characteristics that have the potential to accelerate data processing through neuromorphic systems. However, attaining ideal synaptic functionalities and constructing high‐density vertical synapse arrays are challenging due to issues related to uncontrolled ion migration and constraints in 3D multi‐stacking. Here, a breakthrough using 3D stackable Li ion‐based vertical‐sensing ECRAM (VS‐ECRAM) is presented with an ion‐permeable ultrathin WS2 electrode synthesized through low‐temperature (200 °C) atmospheric‐pressure plasma‐enhanced chemical vapor deposition (AP‐PECVD). The direct AP‐PECVD of the WOx channel layer induces WS2 formation in the surface region, which exhibits sufficient electrical conductivity to function as an electrode. By utilizing the WS2 electrode as an ion‐barrier layer in the VS‐ECRAM synapse, excellent weight update linearity and cycling variability are achieved due to the finely controlled ion migration. Furthermore, a two‐layer stacked 3D VS‐ECRAM is successfully fabricated through the vertical WS2 formation, and independent weight updates without any disturbance are confirmed. Finally, a high pattern recognition accuracy of 95.22% is obtained using a multi‐layer perceptron‐based neural network. Therefore, the proposed 3D stackable WS2‐based VS‐ECRAM exhibits a strong potential for application in high‐density neuromorphic devices with excellent synaptic performances.