Heterostructure Electrode Research Articles

NiCoMn-LDH with core-shell heterostructures based on CoS nanotube arrays containing multiple ion diffusion channels for boosted supercapacitor applications

Nanostructure engineering and composition rationalization are crucial for materials to become candidates for high-performance supercapacitor. Herein, a novel core-shell heterostructured electrode, combining CoS hollow nanorods with NiCoMn-layered double hydroxides (LDH) ternary metal nanosheets, were prepared on carbon cloth by reasonably controlled vulcanization and electrodeposition. By optimizing electrodeposition conditions, the material's structure and properties can be fine-tuned. The enhanced capacitance of the optimized carbon cloth (CC)@CoS/NiCoMn-LDH-300 electrode (4256.0 F g−1) lies in the open space provided by CoS and the establishment of a new charge transfer channel across the interfaces of CC@CoS/NiCoMn-LDH-300 nanosheets. This is further demonstrated by Density functional theory (DFT) simulations based on OH− adsorption energy, which produces faster redox charge kinetics and significantly enhances the electrode's energy storage capacity. The hybrid supercapacitor, integrating the optimized CC@CoS/NiCoMn-LDH-300 electrode with active carbon, demonstrates the highest energy density of 86 Wh kg−1 (under the power density of 850 W kg−1) and the long cycle stability of 89.7%. This study aims to go beyond simple binary LDH by constructing a ternary LDH with a hierarchical core-shell heterostructure to provide an effective and feasible new concept for high-performance supercapacitor electrode materials via rational structure design.

Demonstration of a 3D-Assembled Dual-Mode Photodetector Based on Tubular Graphene/III-V Semiconductors Heterostructure and Coplanar Three Electrodes.

3D assembly technology is a cutting-edge methodology for constructing high-performance and multifunctional photodetectors since some attractive photodetection features such as light trapping effect, omnidirectional ability, and high spatial resolution can be introduced. However, there has not been any report of 3D-assembled multimode photodetectors owing to the lack of design and fabrication guideline of electrodes serving for 3D heterostructures. In this study, a 3D-assembled dual-mode photodetector (3DdmPD) was realized successfully via the clever electrical contact between the rolled-up tubular graphene/GaAs/InGaAs heterostructure and planar metal electrode. Arbitrary switching of three coplanar electrodes makes the as-fabricated tubular 3D photodetector work at the unbiased photodiode mode, which is suitable for energy conservation high-speed photodetection, or the biased photoconductive mode, which favors extremely weak light photodetection, fully showing the advantages of multifunctional detection. In more detail, the Ilight/Idark ratio reached as high as 2 × 104, and a responsivity of 42.3 mA/W, a detectivity of 1.5 × 1010 Jones, as well as a rising/falling time (τr/τf) of 360/370 μs were achieved under the self-driven photodiode mode. Excitingly, 3DdmPD shows omnidirectional photodetection ability at the same time. When 3DdmPD works at the photoconductive mode with 5 V bias, its responsivity is extremely high as 7.9 × 104 A/W and corresponding detectivity is increased to 1.0 × 1011 Jones. Benefiting from the totally independent coplanar electrodes, 3DdmPD is much more easily integrated as arrays that are expected to offer the function of high-speed omnidirectional image-sensing with ultralow power consumption than the planar counterparts which share communal bottom electrodes. We believe that our work can contribute to the progress of 3D-assembled optoelectronic devices.

Bi-Interlayer Strategy for Modulating NiCoP-Based Heterostructure toward High-Performance Aqueous Energy Storage Devices.

Nickel-cobalt (NiCo) phosphides (NCPs) possess high electrochemical activity, which makes them promising candidates for electrode materials in aqueous energy storage devices, such as supercapacitors and zinc (Zn) batteries. However, the actual specific capacitance and rate capability of NCPs require further improvement, which can be achieved through reasonable heterostructural design and loading conditions of active materials on substrates. Herein, novel hierarchical Bi-NCP heterogeneous structures with built-in electric fields consisting of bismuth (Bi) interlayers (electrodeposited on carbon cloth (CC)) are designed and fabricated to ensure the formation of uniform high-load layered active materials for efficient charge and ion transport. The resulting CC/Bi-NCP electrodes show a uniform, continuous, and high mass loading (>3.5mg) with a superior capacitance reaching 1200 Fg-1 at 1 Ag-1 and 4129 mFcm-2 at 1 mAcm-2 combined with high-rate capability and durable cyclic stability. Moreover, assembled hybrid supercapacitors (HSCs), supercapatteries, and alkaline Zn-ion (AZBs) batteries constructed using these electrodes deliver high energy densities of 64.4, 81.8, and 319.1 Whkg-1, respectively. Overall, the constructed NCPs with excellent aqueous energy storage performance have the potential for the development of novel transition metal-based heterostructure electrodes for advanced energy devices.

Unlocking Maximum Synergy: Screen-Printing Fabrication of Heterostructured Microsupercapacitor Stacks.

A cost-effective and scalable approach for the fabrication of heterostructured microsupercapacitors (MSCs) employing screen-printing followed by sequential electrochemical and microspray deposition techniques has been demonstrated. The microsupercapacitor electrode (MSC) that composed of stacked layers of mesoporous carbon, polyaniline (PANI), and MXene hold significant promise for wearable electronics. By adjusting the deposition and spray cycles, the MSC can be readily coated with PANI and MXene. The sequentially stacked two layers of MXene and PANI on the mesoporous carbon spheres (PMPM-MSC) yielded a specific capacitance of 1003 mF cm-2 at 0.5mA cm-2, surpassing the performance of PANI/mesoporous carbon electrode by 1.6 times (771 mF cm-2). After 10,000 cycles of charge and discharge, PMPM-MSCs retained more than 86% of their initial capacitance. In-situ Raman spectroscopy confirmedthe synergistic effects between MXene and PANI within the heterostructured stacked PMPM-MSC electrodes, including enhanced electronic conductivity and improved electrolyte ion dissociation, which aligned with the electrochemical measurement results, such as fast charge/discharge rates and reduced internal and mass transport resistance. This study demonstrates the potential of screen-printed heterostructured MSC stacks with maximum electrochemical synergy for portable and wearable energy storage devices.

Lamellar Nanoporous Metal/Intermetallic Compound Heterostructure Regulating Dendrite-Free Zinc Electrodeposition for Wide-Temperature Aqueous Zinc-Ion Battery.

Aqueous zinc-ion batteries are attractive post-lithium battery technologies for grid-scale energy storage because of their inherent safety, low cost and high theoretical capacity. However, their practical implementation in wide-temperature surroundings persistently confronts irregular zinc electrodeposits and parasitic side reactions on metal anode, which leads to poor rechargeability, low Coulombic efficiency and short lifespan. Here, this work reports lamellar nanoporous Cu/Al2Cu heterostructure electrode as a promising anode host material to regulate high-efficiency and dendrite-free zinc electrodeposition and stripping for wide-temperatures aqueous zinc-ion batteries. In this unique electrode, the interconnective Cu/Al2Cu heterostructure ligaments not only facilitate fast electron transfer but work as highly zincophilic sites for zinc nucleation and deposition by virtue of local galvanic couples while the interpenetrative lamellar channels serving as mass transport pathways. As a result, it exhibits exceptional zinc plating/stripping behaviors in aqueous hybrid electrolyte of diethylene glycol dimethyl ether and zinc trifluoromethanesulfonate at wide temperatures ranging from 25 to -30°C, with ultralow voltage polarizations at various current densities and ultralong lifespan of >4000 h. The outstanding electrochemical properties enlist full cell of zinc-ion batteries constructed with nanoporous Cu/Al2Cu and ZnxV2O5/C to maintain high capacity and excellent stability for >5000 cycles at 25 and -30°C.

Work-function-prompted interfacial charge kinetics in hierarchical heterojunction flexible electrode for efficient capacitive deionization

The growing challenge of water scarcity has spurred extensive research into the development of advanced freestanding pseudocapacitive electrode materials. These electrodes, characterized by their controlled morphology, mechanical complexity, and enhanced desalination capabilities, are advancing water treatment technologies. Additionally, electrodes with interfacially influenced heterostructures demonstrate substantial potential to enhance electrochemical kinetics. However, their widespread adoption is hindered by intricate synthesis procedures and the necessity for multiple discrete components. Herein, the report introduces a cohesive approach that utilizes electrospinning and carbonization to create a freestanding, hierarchically porous nitrogen-doped carbon nanofiber network encapsulating FeNi3 alloy (FeNi3@CNFs) for desalination applications. The method enhances the interfacial effect, mitigates volume changes during sodium ion adsorption and desorption, and improves interfacial stability. By capitalizing on structural and compositional advantages, the novel FeNi3@CNFs electrode delivers outstanding electrochemical properties, including a high desalination capacity (46.47 mg g−1 at 1.2 V), rapid desalination rate (0.77 mg g−1 min−1), and enhanced cyclic durability. Computational analysis via Density Functional Theory shows that the work function prompts a surface charge redistribution at the FeNi3@CNFs heterojunction, optimizing the surface electronic structure and reducing the energy barrier for adsorption. The modification significantly boosts the diffusion kinetics of sodium adsorption. The study delineates a comprehensive methodology for fabricating high-performance heterostructured electrode materials that are effective for capacitive deionization.

MXene-transition metal sulfide composite electrodes for supercapacitors: Synthesis and electrochemical characterization

MXenes are gaining attention due to their unique 2D layered structures, but face limitations like restacking. Transition metal sulfides (TMS) are promising for energy applications, yet suffer from poor conductivity and volume changes during ion processes, leading to capacity fading. Therefore, we borrowed the structure of ZIF-L with a large specific surface area to synthesize TMS. Constructing heterostructures with metallic conductive MXenes and electrochemically active TMSs emerges as a promising strategy to enhance electrochemical performance and address these challenges. In the present paper, Ti3C2TX Mxene is successfully combined with TMS by a facile in-situ reaction. Based on the electrochemical analysis, Mxene/CoS/NF heterostructure electrode presents an area capacitance of 0.91 mAh/cm2, which is 9.78 times of that of pure MXene at a current density of 2 mA/cm2. Impressively, the assembled asymmetric supercapacitor retains a commendable 85.21 % of its original capacity even after 10,000 cycles. The power density of the assembled supercapacitor is 49.15 mW cm−3, and the energy density is 1.42 mWh cm−3. This underscores a practical and effective avenue for advancing research on Mxene-based electrodes.

Microporous α‐Fe2O3@NiO Heterostructures Synthesized for Enhanced Supercapacitor Performance

AbstractIn this present research, we synthesized pure α‐Fe2O3, NiO, and a microporous α‐Fe2O3@NiO heterostructure electrode via the spray pyrolysis method. The microporous α‐Fe2O3@NiO heterostructure electrode, with its highly porous structure, offers a larger electrode‐electrolyte interface, which results in improved electrochemical performance. Specifically, the microporous heterostructure exhibited a higher specific capacitance of 530.87 F/g at a current density of 7 mA/cm2 in a 1 M NaOH electrolyte, as compared to α‐Fe2O3 (187.12 F/g at 7 mA/cm2) and NiO (492.69 F/g at 7 mA/cm2). The microporous α‐Fe2O3@NiO heterostructures exhibited significantly enhanced electrochemical performance as compared to the individual α‐Fe2O3 and NiO samples, owing to the synergistic effect of the heterostructure. Furthermore, the microporous α‐Fe2O3@NiO heterostructure exhibited high specific capacitances and exceptional cycling stability for more than 2000 cycles, indicating their potential as excellent electrode for supercapacitor devices.

Molecule and Microstructure Modulations of Cyano-Containing Electrodes for High-Performance Fully Organic Batteries.

Cyano-containing electrodes usually promise high theoretical potentials while suffering from uncontrollable self-dissolution and sluggish reaction kinetics. Herein, to remedy their limitations, an unprecedented core-shell heterostructured electrode of carbon nanotubes encapsulated in poly(1,4-dicyanoperfluorobenzene sulfide) (CNT@PFDCB) is rationally crafted via molecule and microstructure modulations. Specifically, the linkage of sulfide bridges of PFDCB prevents the active cyano groups from dissolving, resulting in a robust structure. The fluorinations modulate the electronic configurations in frontier orbitals, allowing higher electrical conductivity and elevated output voltage. Combined with the core-shell architecture to unlock the sluggish diffusion kinetics for both electrons and guest ions, the CNT@PFDCB exhibits an impressive capacity (203.5 mAh g-1), remarkable rate ability (127.6 mAh g-1 at 3.0 A g-1), and exceptional cycling stability (retaining 81.1 % capacity after 3000 cycles at 1.0 A g-1). Additionally, the Li-storage mechanisms regarding PFDCB are thoroughly revealed by in situ attenuated total reflection infrared spectroscopy, in situ Raman spectroscopy, and theoretical simulations, which involve the coordination interaction between Li ions and cyano groups and the electron delocalization along the conjugated skeleton. More importantly, a practical fully organic cell based on the CNT@PFDCB is well-validated that demonstrates a tremendous potential of cyanopolymer as the cathode to replace its inorganic counterparts.

Constructing a hierarchical MoS2/MXene heterostructure for efficient capacitive deionization of saline water

Well-dispersed and few-layered molybdenum disulfide (MoS2) has been considered as a suitable electrode material for pseudocapacitive capacitive deionization (CDI) due to its lamellar structure, flexible interlayer intercalation, and high theoretical capacity. However, the serious aggregation, low electrical conductivity and poor hydrophilicity of MoS2 have limited its desalination application. To address these issues, few-layered MXene is used as a conductive and hydrophilic skeleton to support MoS2 nanosheets. In this study, a hierarchical MoS2/MXene heterostructure is fabricated for highly efficient CDI of saline water. The designed heterostructure effectively inhibits the agglomeration of MoS2 and MXene nanosheets, exposes more active electrochemical sites, and improves the wettability, thereby enhancing ion/charge transport. The MoS2/MXene heterostructure electrode exhibits low electrical resistance (3.2 Ω), along with a high specific capacitance of 171.8 F·g-1 at 2 A·g-1. Furthermore, the MoS2/MXene-based CDI electrode demonstrates an excellent desalination capacity of 55.8 mg·g-1 and a fast desalination rate of 13 mg·g-1·min-1. This study paves the way for novel applications in the CDI field.

In-situ surface growth strategy to synthesize MXene@graphdiyne heterostructure for achieving high capacity and desirable stability in lithium-ion batteries

Two-dimensional (2D) heterostructured electrodes, combining graphdiyne (GDY) and MXenes, have exhibited substantial promise in augmenting the mobility of both ionic and electron movement. However, the widespread advancement and industrial utilization have been impeded by intricate manufacturing procedures and insufficient stability. This study introduces a more streamlined, in-situ growth approach for preparing MXene@GDY electrodes, presenting a novel heterostructure. The method simplifies the manufacturing process while enhancing the specific capacity of the electrode and the more stable cycle life of lithium-ion batteries (LIBs). The resulting electrode exhibited an impressive initial specific capacity of 464.4 mA h g−1, maintaining a high capacity of 492.9 mA h g−1 after 100 cycles at 100 mA current density. More importantly, after 1200 cycles, MXene@GDY showed a capacity of 340.7 mA h g−1, significantly outperforming pure MXene, which only reached 122.3 mA h g−1 at a current density of 1.0 A g−1. The proposed in-situ construction of heterojunction on the MXene surface has demonstrated immense potential for designing high-performance electrode materials which are applicable to LIBs.

Electrochemically selective detection of dopamine over serotonin by CuO/Cu2O bulk heterostructure electrode

Electrochemically selective detection of dopamine over serotonin by CuO/Cu2O bulk heterostructure electrode

Synergistic heterointerface engineering of Co9S8/Ni(OH)2 hierarchical nanosheets for remarkable overall water splitting

Sustainable production of hydrogen from electrochemical water spitting by cost-effective and non-precious bifunctional electrocatalyst is of remarkable interest and extremely desirable. Here, a novel hierarchical Co9S8/Ni(OH)2 heterostructure with porous nanosheets was fabricated as the heterogeneous bifunctional electrodes to achieve remarkable water electrolysis. Synergistic coexistence of Co9S8 and Ni(OH)2 nanostructure with crystalline-amorphous feature can induce a large number of chemically coupled heterointerfaces as catalytically accessible active sites to accelerate electron transfer kinetics and enable a super-hydrophilic feature to contact electrolyte and release gas bubbles. Thus, such Co9S8/Ni(OH)2 heterostructure electrode verifies a remarkable electrocatalytic activity with low overpotentials of 274 mV at 100 mA cm−2 for OER and 109 mV at 10 mA cm−2 for HER. As assembled in a lab-made electrolyzer, the Co9S8/Ni(OH)2 heterostructures as bifunctional electrodes enable 1.51 V to achieve an overall water splitting at 10 mA cm−2, along with the outstanding stability at about 100 mA cm−2 up to 55 h. This work paves a bright way to design and construct non-precious materials as effective and advanced electrocatalysts for electrolysis in water.

Designing highly active and CO2 tolerant heterostructure electrode materials by a facile A-site deficiency strategy in Pr1-xBaCo2O5+δ double perovskite

Solid oxide fuel cells (SOFCs) have received continuous attention as an energy conversion device, and the development of highly electrochemically active materials is important. In this work, highly active and CO2 tolerant BaBixCo1-xO3@PrBaCo2O5+δ heterostructure electrode materials were fabricated by a facile A-site deficiency in Pr1-xBaCo2O5+δ double perovskite. A-site excess-deficient Pr0.8BaCo2O5+δ (PBC80) double-perovskite oxide were prepared and designed to induce the self-assembly dissolution to form BaCoO3-δ (BCO) heterostructure through cationic high-concentration deficiency. However, the surface-dissolved alkaline earth metal (Ba2+) readily forms carbonates with CO2, which severely limits the cathode catalytic activity and long-term stability. Thus, bismuth ion-modified PBC80 (BBCO@PBCO) was prepared to further tailor the material properties, which provides more active sites for oxygen reduction reaction (ORR) by strengthening the synergistic interaction between the heterogeneous interfaces. More importantly, BBCO@PBCO exhibits the most stable Area specific resistance (ASR) under CO2 atmosphere, indicating the incorporation of acidic Bi ions effectively mitigated the adsorption and reaction between the material and the acidic gas CO2. These results indicate that the heterostructure induced by A-site deficiency promotes the ORR activity of PrBaCo2O5+δ cathode, while further modification of Bi ions enhances both the electrochemical activity and the stability of the materials, delivering superior resistance to CO2 poisoning.

Ni/Co-MOFs derived NiS2/Co3S4 heterostructured microspheres for high-performance asymmetric supercapacitors

Despite the relatively mature state with respect to the technology for synthesizing transition metal sulfide structure, preparation of heterostructured transition metal sulfides with superior structure and high specific capacitance is still challenging. Herein, we prepared NiS2/Co3S4 heterostructured microspheres by the two-part hydrothermal method using bimetallic MOFs as precursors. By constructing this heterostructure, we aimed to modify the electronic structure of electrode materials to enhance the electrochemical performance. We did not need carbonization in the preparation process and showed good electrochemical properties with a great appearance. Experimental and characterization analysis demonstrated the successful synthesis of NiS2/Co3S4 heterostructured microspheres. The NiS2/Co3S4 electrode manifests a specific capacity of 252.3 mAh/g at 1 A/g. Furthermore, the hybrid asymmetric supercapacitor with NiS2/Co3S4 as the positive electrode has the energy density of 4.29 Wh kg−1 at the power density of 61.99 W kg−1 according to the stack volume. These heterostructured mixed metal sulfide electrode materials with high specific capacity and high rate provide new ideas for research.

CoP Quantum Dots Embedded in Carbon Polyhedra through Co─P─C Bonding Enabling High‐Energy Lithium‐Ion Capacitors

AbstractPhosphides with high theoretical capacity are considered ideal anode materials for lithium‐ion capacitors (LICs), but poor electronic conductivity as well as unsatisfied cyclic stability limits the performance of the phosphides. Here a covalently bonded CoP@C heterostructure is reported, which consists of 5 nm CoP quantum dots (QDs) like pomegranate seeds pinned in carbon polyhedron through interfacial Co─P─C bonding. The ultrafine size of CoP QDs provides more reactive sites and a shorten electrons/ions diffusion path, boosting the specific capacity. The Co─P─C bond induces the energy band variation of CoP and increases the interfacial charge density, bringing about fast kinetics. Besides, the Co─P─C bond introduces a robust pining effect among CoP QDs and carbon polyhedra, greatly improving the structure stability of 5 nm CoP QDs. The CoP@C heterostructure electrode exhibits high capacity (nearly 1000 mAh g−1) and superior cycling stability. It is worth noting that a prototyped LIC full‐cell of YP80//CoP@C presents an impressive high energy density of 172 Wh kg−1 and a power density of 10.8 kW kg−1. Moreover, the LIC possesses an ultra‐long life, retaining 80% after 20,000 cycles. This study offers an effective design for phosphides achieving fast kinetics and superior structure stability through an interfacial bonding approach.

Formation and Electrochemical Properties of Heterostructured Electrodes Based on Cu2O and CuCo2O4

Individual (FTO/Cu2O and FTO/CuCo2O4) and heterostructured (FTO/BiVO4/Cu2O, FTO/BiVO4/CuCo2O4, and FTO/CuCo2O4/Cu2O) electrodes were successfully formed using the electrodeposition method on copper-containing compounds. The morphology of the synthesized electrode systems, which affect the electrochemical properties, was determined. A comparative study of the electrochemical and photoelectrochemical properties of the individual and heterostructured electrodes showed that the modification of the BiVO4 electrode surface with Cu2O and CuCo2O4 oxides led to a significant increase in its efficiency as a photoanode. The deposition of Cu2O nanoclusters onto CuCo2O4 nanoflakes increased the electrochemical stability of the electrode while maintaining its high capacitance.

Construction of MOFs derived porous carbon based core–shell hetero-structure electrode for superior asymmetric supercapacitor

The design of electrode materials with high performance is very important to improve the energy density of supercapacitors (SCs). The combination of electrical double layer capacitor and pseudo-capacitive materials can significantly improve the electrochemical performance of material, but reasonable structural design can inhibit the slow Faraday dynamic mismatch caused by different storage mechanisms. In this study, NiCoB nanosheets were grown on the surface of cobalt metal-organic frameworks (Co-MOF) derived porous carbon (Co-C) by chemical precipitation method to form a core–shell hetero-structure Co-C@NiCoB electrode. The Co-C@NiCoB electrode has the specific capacitance of 2990 F g−1 at 1 A g−1, which is significantly higher than that of Co-C (416 F g−1) and NiCoB (1052 F g−1). In order to further increase the energy density of the device, the carbon nano-sheets with cactus shape as cathode were obtained by calcination of Co-MOF (CNS). The asymmetric SCs with CNS as cathode and Co-C@NiCoB as anode have a high energy density of 66.03 Wh kg−1 at the power density of 763.35 W kg−1 and exceptional cycling life with capacitance retention of 92.1 % over 10,000 cycles.

Photo‐Responsive Molecular Junctions Activated by Perovskite/Graphene Heterostructure Electrode

Photo‐Responsive Molecular Junctions Activated by Perovskite/Graphene Heterostructure Electrode

A Se-induced heterostructure electrode with polymetallic-CoNiFe towards high performance supercapacitors.

Rational regulation of electrode materials with high conductivity and unexceptionable cycling stability is crucial to meet the requirements of high-performance supercapacitors (SCs). Herein, a hierarchical porous kebab-like heterostructure (CoNiFe-Se) is prepared by a facile solvothermal reaction and selenization step. Both experimental and computational results demonstrate that incorporating Se via hydrothermal reaction contributes to modulating the morphology and electronic structure of transition metal carbonate hydroxides. The heterostructured electrode with abundant active sites composed of electroactive polymetallic-CoNiFe imparts excellent charge storage. Additionally, the unique structure of CoNiFe-Se with its heterogeneous interface, oxygen vacancies and cavities improves electrochemical activity, accelerates electron transfer and suppresses the volume expansion during the cycling. As a result, the CoNiFe-Se exhibits excellent electrochemical performance of 5040 mF cm-2 at 1 mA cm-2 and long-term durability with 85.7% retained capacitance after 10 000 cycles. Interestingly, an integrated asymmetric supercapacitor performs well for energy storage. This finding opens a new avenue for developing transition metal carbonate hydroxides using selenization strategies in the field of SCs.