Battery-supercapacitor Hybrid Device Research Articles

Optimization of Solid Electrolytes for Enhanced Battery-Supercapacitor Hybrid Devices: A Leap Toward High-Capacity Retention and Extended Lifespan

Battery-supercapacitor hybrid devices (BSHDs) are meant to fulfil the gap existing between conventional batteries and traditional supercapacitors by exhibiting high-energy and high-power densities, added to excellent cycling stabilities. Nonetheless, effectively integrating the diverse energy storage mechanisms of batteries and supercapacitors remains a significant challenge. Various approaches have been proposed to mitigate these issues ranging from developing advanced microstructures to engineering the interface between electrode|current collector or electrode|electrolyte.1 Previously, our team documented the fabrication of BSHDs capable of undergoing 3,000 charge-discharge cycles while maintaining 81% of their initial capacity.2 This work presents an upgraded iteration of BSHDs which maintains over 95% of the initial capacity and notably increasing the lifespan to over 10,000 cycles. The device in question is composed by a protected graphite anode and a solid electrolyte, composed by either an alginate polymer network or commercially available glass microfiber, with an ionic liquid (PP13-FSI; 1-Methyl-1-propylpyrrolidinium Bis(fluorosulfonyl)imide) as the ion conductive electrolyte. The improvement was achieved by conducting a thorough analysis and optimization of the solid electrolyte in response to the device’s performance during lithium-intercalation, i.e. introducing charge to the anode by forming a stable solid-electrolyte interface (SEI), added to the capability of such said anode as counter electrode during the operation of an activated carbon capacitor.This work therefore discusses the duality between the maximum capacity obtained during the SEI formation process vs the capacity and anode potential retention during the operation of the BSHD, deep diving into the relationship of, inter alia, the thickness of the SEI formed, the increase or decrease of the ion-desolvation resistances, ionic conductivities, and activation energies versus the overall performance of the device.

A Micro Battery Supercapacitor Hybrid Device with Ultrahigh Cycle Lifespan and Power Density Enabled by Bi‐Functional Coating Design

AbstractMicro energy storage devices (MESDs) have emerged as promising energy providers for micro applications due to their integrated performance. However, the limited cycle life and low power density of microbattery, and low energy density of microsupercapacitor have consistently impeded their broader practical implementation. Herein, to obtain a MESD with a long cycle life, excellent power density, and superior energy density, a novel micro battery‐supercapacitor hybrid (MBSH) device is fabricated. Two types of 3D microelectrodes are fabricated, namely, a nanowire network anode based on PEDOT‐TiON and a porous cathode based on Ni(OH)2. Benefiting from the unique hydrophobic characteristics of the PEDOT layer, high electrical conductivity of TiON, and high conductivity, and abundant ion diffusion channels of network microstructure, PEDOT‐TiON NW microelectrodes demonstrate exceptional cycling stability by retaining 70% of their capacity after 40 000 cycles. The achieved MBSH exhibits an extended voltage window ranging from 0 to 1.9 V, impressive power density of 77.5 mW cm−2, and a superior energy density of 55.6 µWh cm−2. Furthermore, it maintains a remarkable capacity retention rate of 71.6% even after undergoing 30 000 cycles. This innovative design paves the way for the developing of high‐performance microdevices with superior electrochemical properties.

Boosting the pseudocapacitance of BiFeO3 by Zn doping for flexible battery-supercapacitor hybrid devices

Perovskite BiFeO3 (BFO) as a type of battery-type electrode materials, usually suffers from poor electrolyte ion transport in the BFO crystal. We propose a novel strategy of Zn doping to improve the ion transport and boost the faradaic pseudocapacitance of BFO for flexible battery-supercapacitor hybrid (BSH) devices. The Zn-doped BFO (Z-BFO-1) with the low Zn doping content, can maintain the crystal structure of BFO and the uniform distributions of elements. The oxygen vacancy content can be increased from BFO to Z-BFO-1, reflecting the influence of the Zn doping on the crystal structure of BFO. The Z-BFO-1 electrode with the stable crystal structure in the charge/discharge process, can provide the highest specific capacitance (223 F g−1 at 0.2 A/g) and the largest Li+ diffusion coefficient (2.386 × 10−11 cm2 s−1) among these BFO-based electrodes with different Zn doping contents. The first-principles calculations reveal that the Zn doping in BFO can significantly enhance the built-in electric fields and greatly lower the Li+ migration energy barriers (from 2.08 eV to 1.43 eV). This flexible MnO2//Z-BFO-1 BSH device with the high energy density (37.5 Wh kg−1 at 0.23 kW kg−1), opens up a new avenue for developing high-performance electrochemical energy storage devices.

Exploring the potency of EDTA-based Ni-Co-MOF nanospheres for highly durable battery-supercapacitor hybrids

Metal Organic Frameworks (MOFs) have emerged as a captivating avenue and advancement in electrode materials, revealing remarkable progress in diverse electrochemical applications. However, despite their apparent potential the persistent hurdles related to specific capacity, degradation in specific energy and power, and reproducibility of results emphasized the demand for focused investigation. This study is objectized to improve the storage capability, stability, and replicability of electrochemical outcomes in a MOF-based battery-supercapacitor hybrid system. To achieve the quest Ethylenediaminetetraacetic acid (EDTA) based Ni-Co-MOF nanospheres were synthesized via hydrothermal route. The bimetallic MOF demonstrates unique redox behavior with a specific capacity of 474.56 C/g at a current density of 1 A/g. Simulating the experimental analysis, it was confirmed that the MOF material exhibits a dominant battery-like nature, with 94.68 % diffusion attributes at a scan rate of 3 mV/s. Integrating nanospheres MOF into an asymmetric hybrid architecture, serving as the positive electrode material, exceptional specific energy and power characteristics reaching 72.58 Wh/kg and 8500 W/kg respectively. Moreover, the MOF-based hybrid configuration demonstrated remarkable cycle stability, retaining 93.2 % of its capacity after undergoing 10,000 charge discharge cycles. Notably, the hybrid device exhibited excellent reproducibility, with a specific energy output of 71.43 Wh/kg after 40 days and 70.33 Wh/kg after 80 days under standard environmental conditions. Additionally, the simulation approach results indicated that the battery-supercapacitor hybrid device exhibited a diffusion dominance of 76.42 % at a scan rate of 30 mV/s and a capacitive contribution of 61.66 % at 100 mV/s. These promising findings underscore the potential of Ni-Co-MOF-based hybrid configuration as a strong entrant for practical applications in efficient energy storage systems.

High performance MnNbS@MXene hybrid electrode for battery-supercapacitor hybrid device and biomedical applications

Hybrid energy storage devices have obtained a lot of interest because of their remarkable capacitance, high stability and multiple applications. The energy-storage capabilities of transition metal sulfides, such as MnNbS, have expanded beyond the domain of oxide-based materials. Transition metal sulfides and the MXene-based nano-architecture materials have been praised because of their synergistically enhanced conductivity and redox flexibility. Manganese niobium sulfide (MnNbS) binary electrode material was synthesized using the hydrothermal method. The MnNbS-MXene nanocomposite electrode was designed to improve the electrochemical characteristics. It exhibited a superior specific capacity (Qs) of 1094 C/g or 1562.85F/g at 1.5 A/g. The hybrid material (MnNbS-MXene) and activated carbon (AC) were used to make the asymmetric hybrid supercapacitors (MNS-MXene//AC). The hybrid device delivered extraordinary Qs of 153.23 C/g, energy density of 35.77 Wh/kg, and power density of 2800 W/kg. To estimate the capacity retention (CR), the device was measured up to 6000 cycles. It also revealed an astonishing CR of 91 %, which is much greater than that of pure MXene//AC and MnNbS//AC. Besides, the MnNbS-MXene//AC nanocomposite electrode is used as a chemical sensor to detect hydrogen peroxide (H2O2). The MnNbS-MXene showed high sensitivity against the H2O2. The device showed the response up to a wide range of H2O2 (1 mM-5mM). Our research presents a perspective and practical application for producing high-performance electrode material based on transition metal sulfide composites and chemical sensors to detect cancerous cells in the body.

Regulating the Nanosize Effect of LiCoO2 for High-Performance Battery-Supercapacitor Hybrid Devices

Regulating the Nanosize Effect of LiCoO₂ for High-Performance Battery-Supercapacitor Hybrid Devices

Pyridine 3,5-dicarboxylate-based metal-organic frameworks as an active electrode material for battery-supercapacitor hybrid energy storage devices.

Efficient energy storage and conversion is crucial for a sustainable society. Battery-supercapacitor hybrid energy storage devices offer a promising solution, bridging the gap between traditional batteries and supercapacitors. In this regard, metal-organic frameworks (MOFs) have emerged as the most versatile functional compounds owing to their captivating structural features, unique properties, and extensive diversity of applications in energy storage. MOF properties are governed by the structure and topological characteristics, which are influenced by the types of ligands and metal nodes. Herein, MOFs based on pyridine 3,5-dicarboxylate (PYDC) ligand in combination with copper and cobalt are electrochemically analyzed. Owing to the promising initial characterization of Cu-PYDC-MOF, a battery supercapacitor hybrid device was fabricated, comprising Cu-PYDC-MOF and activated carbon (AC) electrodes. The device showcased energy and power density of 17 W h kg -1 and 2550 W kg -1, respectively. Dunn's model was employed to gain deeper insights into the capacitive and diffusive contributions of the device. With their performance and versatility, the PYDC-based MOFs stand at the forefront of energy technology, ready to power a brighter future for upcoming generations.

Elucidating the redox activity of cobalt-1,2,3,4-cyclopentane-tetracarboxylic acid and 1,2,4,5-benzene-tetracarboxylic acid-based metal-organic frameworks for a hybrid supercapacitor.

The development of electrode materials with extraordinary energy densities or high power densities has experienced a spectacular upsurge because of significant advances in energy storage technology. In recent years, the family of metal-organic frameworks (MOFs) has become an essential contender for electrode materials. Herein, two cobalt-based MOFs are synthesized with distinct linkers named 1,2,4,5-benzene-tetra-carboxylic acid (BTCA) and 1,2,3,4-cyclopentane-tetracarboxylic acid (CPTC). Investigations have been rigorously conducted to fully understand the effect of linkers on the electrochemical properties of Co-based MOFs. The best sample among the MOFs was used with activated carbon to create a battery-supercapacitor hybrid device. Due to its noteworthy results, specific capacity (100.3 C g-1), energy density (23 W h kg-1), power density (3400 W kg-1) and with the lowest ESR value of 0.4 Ω as well as its 95.4% capacity retention, the fabricated hybrid device was discovered to be very appealing for applications demanding energy storage. An approach for evaluating battery-supercapacitors was employed by quantifying the capacitive and diffusive contributions using Dunn's model to reflect the bulk and surface processes occurring during charge storage. This study fills the gap between supercapacitors and batteries, as well as providing a roadmap for creating a new generation of energy storage technologies with improved features.

Elevating Energy Density in Li-Ion Batteries through Electrospun Nanotubular Titania-Polymer Interfaces

The introduction of new anode materials holds the potential to address critical safety concerns associated with current commercialized options in Li-ion batteries. Graphite, while widely used, poses challenges due to its low charging potential, which contributes to the growth of dendrites and safety risks. In contrast, titania-based materials present an appealing solution. Their higher operational potential not only curbs dendrite formation but also prevents the formation of a thick solid electrolyte interface (SEI). Furthermore, the limited volume expansion during lithiation significantly enhances their safety profile, differentiating them from graphite-based anodes such as those incorporating silicon.In this new study, titania-based nanotubular structures were created for high-energy Li-ion batteries using a novel electrospinning technique. Titania-based nanotubes were synthesized, modified for optimal charge transfer, and combined with a self-standing electrode through electrospinning with PVDF. The effects of various thermal treatment conditions on Li-ion diffusion were explored using electrochemical methods. The best charge transfer kinetics were observed in the sample treated for 10 hours. After optimizing the electrospinning process, a fully embedded nanotube fibrous structure was achieved, confirmed by electron microscopy. The use of a polymeric network removed the need for metallic current collectors, boosting energy density by 14%. These electrospun electrodes show great promise for high-energy applications.This work was supported by the M-era.Net 2019 call project “LiBASED Li-ion BAttery-SupErcapacitor Hybrid Device”. The research was co-funded by the Turkish Scientific and Technological Research Council (TUBITAK) with project number 119N758.

Evaluating the feasibility of the spinel-based Li4Ti5O12 and LiNi0.5Mn1.5O4 materials towards a battery supercapacitor hybrid device

Hybrid devices consisting of energy-dense lithium-ion battery chemistry and power-dense supercapacitors in a single unit cell are vital to improve the energy density of supercapacitors. Herein, we demonstrate a lithium-ion capacitor containing a composite of LiNi0.5Mn1.5O4 and a high surface area carbon composite as the cathode and carbon-coated Li4Ti5O12 as an anode. The composite cathode combines redox and adsorption mechanisms to store ions, producing more capacity. In contrast, the nanostructure anode can store Li-ions through a faster diffusion-type intercalation process. As a result, the lithium-ion capacitor delivers energy densities of 48 and 30 Wh kg−1 at power densities of 250 and 7900 W kg−1, respectively. Furthermore, upon cycling at 1 A g−1, the full cell retains ∼70 % specific capacitance till 4000 cycles. The use of spinel materials in both electrodes boosts the electrochemical performances of this lithium-ion capacitor because of their inherent properties like stable phase and 3D network-type structure for Li-ion diffusion. Additionally, battery-type cathodes like LiNi0.5Mn1.5O4 (4.7 V vs. Li/Li+) with a wider potential window improve the energy density, whereas better safety and cycling stability arise from the zero-strain Li4Ti5O12 anode. The studies on impedance, self-discharge, and leakage current analyses prove the practical feasibility of the lithium-ion capacitor.

Rapid synthesis of high-entropy antimonides under air atmosphere using microwave method to ultra-high energy density supercapacitors

Electrode materials based on battery-type energy storage principles have high capacity and energy density. However, the drastic structural volume changes caused by electrochemical reaction processes reduce the cyclic durability of the materials. The construction of high-entropy structures can enhance the material structure to accommodate the volume changes during ion embedding/detachment. In this study, a new high-entropy antimonide battery-type electrode material was synthesized for the first time using a domestic microwave oven under air atmosphere. Its lattice and structure were stabilized using high-entropy multi-element system to improve the electrode cycling stability while ensuring its high capacity. The high-entropy antimonides have a capacity of 1850.0 C g−1 at 1 A g−1 and maintain 82.0 % of the initial capacity after 10,000 cycles. Furthermore, the battery-supercapacitor hybrid device (BSH) assembled with Bi2O3 @single-walled carbon nanotube (SWCNT) has a reversible capacity of 600.0 C g−1, and the BSH showed an energy density of 125.0 Wh kg−1 at a power density of 750.0 W kg−1. The BSH meets the standard of secondary batteries, which provides a new feasible method for building energy storage devices with good performance.

Cauliflower like porous structure of cobalt niobium sulfide@carbon nanotubes for electrode materials to enhance the redox activity in the battery-supercapacitor hybrid device

Cauliflower like porous structure of cobalt niobium sulfide@carbon nanotubes for electrode materials to enhance the redox activity in the battery-supercapacitor hybrid device

Dual-ion (de)intercalation into high-entropy perovskite oxides for aqueous alkaline battery-supercapacitor hybrid devices

High-entropy perovskite oxides (HEPOs) suffer from inferior stability in high-power battery-supercapacitor hybrid (BSH) devices. Therefore, revealing their energy storage mechanism is extremely important for optimizing appliance stability. Herein, La0.7Bi0.3Mn0.4Fe0.3Cu0.3O3 nano-HEPO exhibits the dual-ion energy storage mechanism in aqueous alkaline BSH devices. The rapid deintercalation of oxygen anions from the (sub)surface facilitates the intercalation of hydrogen cations into the bulk during charging; however, the deintercalation of hydrogen cations upon the discharge process is hindered because of the surface filling with oxygen vacancies, resulting in an irreversible phase transition and volumetric expansion. Meanwhile, the evolution of surface oxygen species leads to the weak binding between the surface metal-oxygen polyhedron and the bulk, causing severe capacity deterioration due to the active cation leaching and surface inactive La(OH)3 aggregation. Finally, optimal strategies are presented based on the dual-ion intercalation chemistry of HEPOs for application in high-performance BSH devices with long service life.

Morphological and electronic modification of NiS2 for efficient supercapacitors and hydrogen evolution reaction

Rational design of highly active and low-cost electrode material toward energy storage and hydrogen evolution reaction (HER) is promising but still challenging. Herein, we present V-doped pyrite NiS2 nanosheets grown on carbon cloth (VNS/CC) as an efficient electrode material for supercapacitors and HER. The optimal 20% VNS/CC electrode exhibited ultra-high specific capacity (1970 F g−1 at 1 A g−1) with excellent long-term cycling stability (100% retention over 6000 cycles). The 20% VNS/CC//AC battery-supercapacitor hybrid device presented high-energy and high-power performances (e.g., 64.4 W h kg−1 at 799 W kg−1) and excellent cycling stability. Furthermore, the 20% VNS/CC exhibited superior HER performance, including low overpotential and exceptional stability. The combined experiments and density functional theory (DFT) calculations revealed that the superior supercapacitor and HER performance of VNS/CC are attributed to the doping of V on the NiS2 surface/subsurface: (i) significant modulation of the morphology to promote the formation of independent nanosheet structures with abundant active sites and induced pseudocapacitance effects; (ii) practical tuning of the NiS2 electronic structure to convert the semiconductor characteristics into metallic properties with high conductivity, and (iii) optimize the adsorption/dissociation energy of water molecules to enhance the Volmer step reaction rate in alkaline solutions.

Synthesis of the sandwich-type NiMn2O4@N-C@MnO2 core-shell nanostructured materials for the high-performance battery-supercapacitor hybrid devices

In this study, we successfully synthesized the sandwich-type NiMn2O4@N-C@MnO2 core-shell nanostructures. The NiMn2O4@N-C@MnO2 had a unique structure compared with the core-shell nanostructures previously reported. The microvillous nitrogen-doped carbon (NC) was considered as a highly conductive material, similar to a highway network, which facilitated the transport of electrons, improved the conductivity of core-shell nanomaterials, and acted as a buffer during the repeated charge-discharge cycles, thereby improving the overall stability of the nanomaterials. The introduction of N could increase the active sites for a redox reaction to a certain extent. Among all the prepared electrodes, NiMn2O4@N-C@MnO2-2 exhibited excellent performance. The NiMn2O4@N-C@MnO2-2//AC BSH device achieved an energy density of 34.29 W h kg−1 at a current density of 10 mA cm−2 when the power density was 946.75 W kg−1. In addition, the device retained 96.68 % of the initial specific capacitance after charge-discharge 30,000 cycles, which was better than most related studies previously reported. The excellent electrochemical performance of the device indicates that sandwich-type NiMn2O4@N-C@MnO2 core-shell nanomaterials have great application potential in the development of energy storage and conversion equipment.

Microwave-Assisted Rational Designed CNT-Mn3 O4 /CoWO4 Hybrid Nanocomposites for High Performance Battery-Supercapacitor Hybrid Device.

Extensive research interest in hybrid battery-supercapacitor (BSH) devices have led to the development of cathode materials with excellent comprehensive electrochemical properties. In this work, carbon nanotube (CNT)-Mn3 O4 /CoWO4 triple-segment hybrid electrode is synthesized by using a two-step microwave-assisted hydrothermal route. Systematic physical characterization revealed that, with the assistance of microwave, granular Mn3 O4 and spheroid-like CoWO4 with preferred orientation, and oxygen vacancies are stacked or arranged on CNTs skeletons to construct a rational designed hybrid nanocomposite with abundant heterointerfaces and interfacial chemical bonds. Electrochemical evaluations show that the synergistic cooperation in CNT-Mn3 O4 /CoWO4 resulted in an ultra-high specific capacity (1907.5Cg-1 /529.8mAhg-1 at 1Ag-1 ), a wide operating voltage window (1.15V), the satisfactory rate capability (capacity maintained at 1016.5Cg-1 /282.3mAhg-1 at 15Ag-1 ), and excellent cycling stability (117.2% initial capacity retention after 13000 cycles at 15Ag-1 ). In addition, the assembled CNT-Mn3 O4 /CoWO4 //N doped porous carbon (NC) BSH device delivered a stable working voltage of 2.05V and superior energy density of 67.5Whkg-1 at power density of 1025Wkg-1 , as well as excellent stability (92.2% capacity retained at 5Ag-1 for 12600 cycles). This work provides a new and feasible tactic to develop high-performance transition metal oxide-based cathodes for advanced BSH devices.

Insight into Electrochemical Performance of Nitrogen-Doped Carbon/NiCo-Alloy Active Nanocomposites.

Nanocomposites containing Ni or Co or NiCo alloy and nitrogen-doped carbon with diverse ratios have been prepared and utilized as active elements in supercapacitors. The atomic contents of nitrogen, nickel, and cobalt have been adjusted by the supplement amount of Ni and Co salts. In virtue of the excellent surface groups and rich redox active sites, the NC/NiCo active materials exhibit superior electrochemical charge-storage performances. Among these as-prepared active electrode materials, the NC/NiCo1/1 electrode performs better than other bimetallic/carbon electrodes and pristine metal/carbon electrodes. Several characterization methods, kinetic analyses, and nitrogen-supplement strategies determine the specific reason for this phenomenon. As a result, the better performance can be ascribed to a combination of factors including the high surface area and nitrogen content, proper Co/Ni ratio, and relatively low average pore size. The NC/NiCo electrode delivers a maximum capacity of 300.5 C g-1 and superior capacity retention of 92.30% after 3000 unceasing charge-discharge cycles. After assembling it into the battery-supercapacitor hybrid device, a high energy density of 26.6Wh kg-1 (at 412W kg-1 ) is achieved, comparable to the recent reports. Furthermore, this device can also power four light-emitting-diode (LED) demos, suggesting the potential practicability of these N-doped carbon compositing with bimetallic materials.

Urea-Based Deep Eutectic Solvent with Magnesium/Lithium Dual Ions as an Aqueous Electrolyte for High-Performance Battery-Supercapacitor Hybrid Devices

A new deep eutectic solvent (DES) made from urea, magnesium chloride, lithium perchlorate and water has been developed as the electrolyte for battery-supercapacitor hybrid devices. The physicochemical characteristics of DES electrolytes and potential interactions between electrolyte components are well analyzed through electrochemical and spectroscopic techniques. It has been discovered that the properties of DES electrolytes are highly dependent on the component ratio, which allows us to engineer the electrolyte to meet the requirement of the battery application. Perylene tetracarboxylic di-imide and reduced graphene oxide ha ve been combined to produce a composite (PTCDI/rGO) that has been tested as the anode in DES electrolyte. This composite shows that the capacitive contribution is greater than 90% in a low scan rate, resulting in the high rate capability. The PTCDI/rGO electrode exhibits no sign of capacity degradation and its coulombic efficiency is close to 99% after 200 cycles, which suggests excellent reversibility and stability. On the other hand, the electrochemical performance of lithium manganese oxide as the cathode material is studied in DES electrolyte, which exhibits the maximum capacity of 76.5 mAh/g at 0.03 A/g current density. After being successfully examined in terms of electrode kinetics, capacity performance, and rate capability, the anode and cathode materials are combined to construct a two-electrode system with DES electrolyte. At a current density of 0.03 A/g, this system offers 43.5 mAh/g specific capacity and displays 55.5% retention of the maximum capacity at 1 A/g. Furthermore, an energy density of 53 Wh/kg is delivered at a power density of 35 W/kg.

Rapid microwave-assisted synthesis strategy of dual-cationic molybdates as high-performance electrodes for alkaline battery-supercapacitor hybrid devices

Metal molybdates have attracted considerable attention owing to the development and application of electrochemical energy storage materials and catalysts. However, a long reaction period is normally required during the preparation process of metal molybdates such as classic hydrothermal method. Herein, two groups of dual-cationic metal molybdates, CoxNi1−xMoO4 and CoxCa1−xMoO4 (0≤ x ≤1), were synthesized via a facile and rapid microwave-assisted method. The reaction time was shortened to 30 min via microwave irradiation. The additional redox reactions and increased pore structures induced by extra cation helped the dual-cationic metal molybdates to improve the capacity and extend the cycling span. The optimal electrode in each group was used as the positive electrode, and an active carbon (AC) electrode was used as the negative electrode to assemble the alkaline aqueous battery-supercapacitor hybrid (BSH) device, respectively. The two assembled BSH devices exhibited excellent application prospects and could achieve the highest energy density of 11.1 Wh kg−1 and 8.4 Wh kg−1, respectively. Apart from promising BSH devices, this research also provides a green and rapid synthesis strategy for fabricating other molybdenum-based materials for exceptional properties.

Synthesis of the sandwich-type MnMoO4@NiMoO4@Mn2O3 core-shell nanostructured materials and their application in the high-performance battery-supercapacitor hybrid devices

We synthesized the sandwich-type of MnMoO4@NiMoO4@Mn2O3 core-shell nanosheet arrays (MMNM) that were grown on nickel foams (NFs) via a two-step controllable hydrothermal reaction. Compared with the previously reported core-shell materials, the structure of MMNM series materials was more unique and abundant, and its application prospect was extremely broad. The electrochemical properties of the prepared electrodes were tested in a three-electrode system, among which the MMNM-2 electrode exhibited the best electrochemical performance. The battery-supercapacitor hybrid device (MMNM-2 //AC BSH device) fabricated with MMNM-2 and activated carbon (AC) as the positive electrode and the negative electrode, respectively, achieved a high energy density of 49.99 W h kg−1 at a power density of 877.87 W kg−1. Moreover, the MMNM-2//AC BSH device exhibited better cycling stability than most previously reported BSH devices, with a high capacity retention of 96.03% after 20,000 cycles at a current density of 10 mA cm−2. The excellent electrochemical performance indicated the potential application of MMNM-2 in new energy storage devices.