High Electrochemical Performance Research Articles

Superior polysulfide adsorption ability by using Ti3C2 nanosheets as effective reservoirs for high electrochemical performance

AbstractBACKGROUNDA large amount of research has improved electrochemical performance by strengthening the chemical affinity by using polar materials in lithium–sulfur batteries. However, only some of this research has focused on the relationship between structure and polysulfide adsorption ability.RESULTSIn this work, a Ti3C2 nanosheet structure has been applied as sulfur host matrix to improve electrochemical performance. Due to the nanosheet structure, the polysulfide was able to diffuse between the Ti3C2 layers, therefore improving the catalytic effect of the polysulfide. Moreover, the space between the Ti3C2 layers can store the soluble polysulfide as an effective reservoir. As a result, the traditional shuttle effect of the polysulfide could be efficiently inhibited.CONCLUSIONTherefore, the as‐prepared Ti3C2/S composites exhibited high specific capacity, high rate performance, and stable cycle performance. All these superior electrochemical performances are attributed to the presence of the Ti3C2 nanosheet. © 2022 Society of Chemical Industry (SCI).

Hierarchical porous carbons as sulfur host to restrain polysulfide migration for high-electrochemical performance Li–S batteries

Hierarchical porous carbons as sulfur host to restrain polysulfide migration for high-electrochemical performance Li–S batteries

Nitrogen and Oxygen Co‐doped Hierarchical Porous Carbon by One‐Step Pyrolysis of PEG/Melamine/MgO Bulks for High‐Performance Supercapacitors

AbstractSimple and convenient protocols for fabricating heteroatom‐doped hierarchical porous carbon are highly imperative owing to their superior electrochemical performance. Here, nitrogen and oxygen co‐doped hierarchical porous carbon materials (NOPCs) are facilely prepared by the one‐step carbonization of PEG‐200/melamine/MgO bulks within ten minutes. The solid bulks enable the synthesis more conveniently, and make the NOPCs have a uniform structure and high electrochemical performance. The optimized products, NOPC‐900, has the largest specific surface area (the SBET of 1248 m2 g−1), abundant mesopore structures (average pore diameter of 9.40 nm), with thin carbon walls (3–10 graphene layers), and the effective heteroatom doping (the content of N atom is 2.67 at.%, and O atom is 12.49 at.%). As a result, The NOPC‐900 displays the specific capacitance of 324 F g−1 at 0.5 A g−1 and a low IR drop of 0.018 V at 50 A g−1. When assembling NOPC‐900 into a symmetric two‐electrode supercapacitor, it presents the cell capacitance of 54.18 F g−1 at 0.5 A g−1 and perseveres 84.6 % of initial capacitance at 10 A g−1. Meanwhile, the energy density of 19.12 Wh kg−1 is achieved at the power density of 425 W kg−1. The convenient preparation approach and excellent electrochemical performance render the NOPCs to be promising candidates for supercapacitor application.

A polybromide confiner with selective bromide conduction for high performance aqueous zinc-bromine batteries

Aqueous zinc-bromine batteries are promising energy storage systems. The non-flow setup largely reduces the cost, and the application of Br− containing electrolytes transform the volatile charged product Br2 to polybromide. However, the shuttling of soluble polybromide species causes poor coulombic efficiency and corrosion of the negative electrode. Herein, we design a composite positive electrode of polybromide confiner and conductive agent for non-flow zinc-bromine batteries. The (2-bromoethyl) trimethylammonium bromide and hexyl bromide are grafted as the side chains of poly(biphenyl pyridine). The obtained PBP-BTAB-HB polymer provides selective bromide conduction whereas hinders polybromide diffusion through steric hindrance. It forms uniform layer on the Super P carbon particles, resulting in the composite electrode with facile electron and bromide transports as well as polybromide restriction. In the aqueous zinc-bromine battery, the positive electrode presents high coulombic, voltage and energy efficiencies of 92%, 81% and 74%, respectively, at 8 mA cm−2 with 2 mAh cm−2 charge capacity. Stable cycling is achieved for 1200 cycles with 99.8% capacity retention. The high electrochemical performance is preserved at a low temperature of 0 °C. A pouch cell is also demonstrated, delivering 18 mAh capacity at 100 mA. Our work offers a promising path for high-performance zinc-bromine batteries.

A graphitized hierarchical porous carbon as an advanced cathode host for alkali metal-selenium batteries

• One-step activation-free synthesis of hierarchical porous carbon is achieved by CO 2 erosion. • HPC possesses high electronic conductivity with controllable graphitization degree. • The excellent specific surface area and voids of HPC can buffer deposition and drastic volume breath. • HPC/Se shows high excellent electrochemical performance as cathode for alkali metal-selenium batteries. Selenium cathode, of high volumetric energy density and compatibility with safe/cheap carbonate electrolyte, are plagued by low active material utilization, limited rate capability and fast capacity fading. Therefore, a carbon host, capable of speeding electron transfer, facilitating Li + diffusion and buffering drastic volume breath, is greatly demanded. Herein, a graphitized hierarchical porous carbon is prepared by metallothermic reduction reaction of CO 2 , and employed as cathode host for alkali metal-Se batteries. With high electronic conductivity, ultrahigh specific area (1740 m 2 g −1 ) and abundant porosity (1.76 cm 3 g −1 ), this carbon host after Se infiltrating exhibits an initial capacity of 994 mAh g −1 and a reversible capacity of 538 mAh g −1 at 0.5C in the initial cycle for lithium-selenium batteries. In addition, a reversible capacity of 451 mAh g −1 can still be achieved at a current density of 2C, with a low capacity decay rate of about 0.037% per cycle in subsequent 800 cycles. In further tests, HPC/Se cathode also shows superior rate capabilities and stable cyclability for sodium-selenium batteries and potassium-selenium batteries.

Binary self-assembly of ordered Bi4Se3/Bi2O2Se lamellar architecture embedded into CNTs@Graphene as a binder-free electrode for superb Na-Ion storage

With the development of various flexible electronic devices, flexible energy storage devices have attracted more research attention. Binder-free flexible batteries, without a current collector, binder, and conductive agent, have higher energy density and lower manufacturing costs than traditional sodium-ion batteries (SIBs). However, preparing binder-free anodes with high electrochemical performance and flexibility remains a great challenge. In this study, a binary self-assembly composite of an ordered Bi4Se3/Bi2O2Se lamellar architecture wrapped by carbon nanotubes (CNTs) was embedded in graphene with strong interfacial interaction to form Bi2O2Se/Bi4Se3@CNTs@rGO (BCG), which was used as a binder-free anode for SIBs. A unique “one-changes-into-two” phenomenon was observed: the layered Bi2Se3 was transformed into a unique layered Bi4Se3/Bi2O2Se heterojunction structure, which not only provides more electrochemical channels but also reduces internal stress to improve the stability of the material structure. BCG-2 showed excellent sodium-ion storage, delivering a reversible capacity of 346 mA h/g at 100 mA/g and maintaining a capacity of 235 mA h/g over 50 cycles. Even at a high current density of 1 A/g, it retains a capacity of 105 mA h/g after 1000 cycles. This unique design concept can also be employed in synthesizing other binder-free electrodes to improve their properties.

Construction of NiCoZnS materials with controllable morphology for high-performance supercapacitors

A facile two-step hydrothermal approach with post-sulfurization treatment was put forward to construct the mixed transition metal sulfide (NiCoZnS) with a high electrochemical performance. The different morphologies of NiCoZnS materials were successfully fabricated by adjusted the Ni/Co molar ratio of the NiCoZn(OH)F precursor. Moreover, the in situ phase transformation from the NiCoZn(OH)F phase to Zn0.76Co0.24S and NiCo2S4 phases and lattice defects via the S2− ion-exchange were determined by x-ray diffractometer, transmission electron microscopy and x-ray photoelectron spectroscopy techniques, which improved electric conductivity and interfacial active sites of the NiCoZnS, and so promoted the reaction kinetics. Significantly, the urchin-like NiCoZnS1/1 prepared at the Ni/Co molar ratio of 1.0 exhibited promising electrochemical performances with high capacitance and excellent cycling stability. Furthermore, the asymmetric device (NiCoZnS//AC) using NiCoZnS1/1 as the positive electrode had excellent supercapacitor performances with an energy density of 57.8 Wh·kg–1 at a power density of 750 W·kg–1 as well as a long cycle life (79.2% capacity retention after 10 000 cycles), indicating the potential application in high-performance supercapacitors.

Highly Capacitive Mesoporous Polyaniline Spheres as Scalable and High Electrochemical Performance Supercapacitor Electrode

AbstractThis article demonstrates morphological based fabrication of Polyaniline mesopores (PANIMS) via the standard polymerization approach using Triton as an additive and 0.1 M H2SO4 as an electrolyte to achieve improved specific capacity (736 F g−1) in contrast to reported bulk PANI as well as PANI sphere morphologies. PANIMS1 exhibit long cyclic stability and capacitive retention ∼83 % in 0.1 M H2SO4 electrolyte after 5000 cycles. This easy and low‐cost fabrication of PANIMS was conducted by varying minimal amount of Triton in 0.1 M H2SO4 electrolyte solution to form mesopores. The adsorption and desorption isotherm of the mesopores suggests a specific surface area of 50.9 m2 g−1with a pore diameter of 2.2 nm. The protocol followed to form these PANIMS involves the variation of surfactant Triton to achieve sphere morphology thereby enhancing the charge storage property of PANI. These spheres also possess an enhanced electrical conductivity to be around ∼23 S/m than their bulk counterpart. The electrochemical assays show that there is excellent electrolyte ion penetration in the H2SO4 electrolyte which promotes a rapid ion transport to the PANIMS active sites. Also, a low value of Rct ∼2.17 Ω helps in giving a good capacitive performance of the PANIMS1 electrode. The electrochemical impedance spectroscopy (EIS) analysis shows a phase degree at 68°, response frequency at 0.38 Hz and time constant at 2.63 s. The study shows the present mesopores morphology of PANI projects to be one of the good electrode candidates for supercapacitor applications.

Rational Design Strategy of Novel Energy Storage Systems: Toward High-Performance Rechargeable Magnesium Batteries.

Rechargeable magnesium batteries (RMBs) are promising candidates to replace currently commercialized lithium-ion batteries (LIBs) in large-scale energy storage applications owing to their merits of abundant resources, low cost, high theoretical volumetric capacity, etc. However, the development of RMBs is still facing great challenges including the incompatibility of the electrolyte and the lack of suitable cathode materials with high reversible capacity and fast kinetics of Mg2+ . While tremendous efforts have been made to explore compatible electrolytes and appropriate electrode materials, the rational design of unconventional Mg-based battery systems is another effective strategy for achieving high electrochemical performance. This review specifically discusses the recent research progress of various Mg-based battery systems. First, the optimization of electrolyte and electrode materials for conventional RMBs is briefly discussed. Furthermore, various Mg-based battery systems, including Mg-chalcogen (S, Se, Te) batteries, Mg-halogen (Br2 , I2 ) batteries, hybrid-ion batteries, and Mg-based dual-ion batteries are systematically summarized. This review aims to provide a comprehensive understanding of different Mg-based battery systems, which can inspire latecomers to explore new strategies for the development of high-performance and practically available RMBs.

3D Architecturing Strategy on the Utmost Carbon Nanotube Fiber for Ultra‐High Performance Fiber‐Shaped Supercapacitor

AbstractFiber‐shaped supercapacitors (FSSCs) are the most state‐of‐the‐art power supplies suitable for wearable devices, but the intrinsically limited cylindrical space of fibers restricts their high electrochemical performance, which must be overcome with a delicate and systematic architectural process. Here, a simple but effective 3D architectural strategy for fabricating FSSCs with high performance and flexibility is proposed. Highly conductive liquid crystal spun carbon nanotube fiber (CNTF) is an excellent 1D core fiber for the electrophoretic deposition of graphene oxide (GO). The deposited GO forms a vertical 3D structure on the CNTF (VG@CNTF), which can be successfully preserved by a consecutive coating of pseudocapacitive active materials onto the surface of VG. Notably, a solid‐state asymmetric FSSC shows an outstanding performance of 65 Wh kg−1 at 100 kW kg−1 and exceptional stability and flexibility (capacitance retention of 98.60% at bending angles of 90° and 93.1% after 5000 bending cycles). This work can provide new insight into the development of high‐performance FSSCs for practical wearable applications.

Strategies for Harnessing High Rate and Cycle Performance from Graphite Electrodes in Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) have been lauded as the next-generation energy storage systems on account of their high voltage capabilities and low costs and the high abundance of potassium resources. However, the practical utility of PIBs has been heavily encumbered by severe K metal dendrite formation, safety issues, and insufficient electrochemical performance during operations─indeed critical issues that underpin the need for functional electrolytes with high thermal stability, robust solid-electrolyte interphase (SEI)-forming capabilities, and high electrochemical performance. In a bid to establish a knowledge framework for harnessing high rate capabilities and long cycle life from graphite negative electrodes, this study presents the physical properties and electrochemical behavior of a high K+ concentration inorganic ionic liquid (IL) electrolyte, K[FSA]-Cs[FSA] (FSA- = bis(fluorosulfonyl)amide) (54:46 in mol), at an intermediate temperature of 70 °C. This IL electrolyte demonstrates an ionic conductivity of 2.54 mS cm-1 and a wide electrochemical window of 5.82 V. Charge-discharge tests performed on a graphite negative electrode manifest a high discharge capacity of 278 mAh g-1 (0.5 C) at 70 °C, a high rate capability (106 mAh g-1 at 100 C), and a long cyclability (98.7% after 450 cycles). Stable interfacial properties observed by electrochemical impedance spectroscopy during cycling are attributed to the formation of sulfide-rich all-inorganic SEI, which was examined through X-ray photoelectron spectroscopy. The performance of the IL is collated with that of an N-methyl-N-propylpyrrolidinium-based organic IL to provide insight into the synergism between the highly concentrated K+ electrolyte at intermediate temperatures and the all-inorganic SEI during electrochemical operations of the graphite negative electrode.

A hierarchically combined reduced graphene oxide/Nickel oxide hybrid supercapacitor device demonstrating compliable flexibility and high energy density

This work demonstrates a hierarchical structure design with mixed holey graphene oxide (HGO) and Ni(OH)2 active material layer made by one-pot hydrothermal reaction clinging to Nickel foam as backbone and ice-template oriented graphene oxide (GO) aerogel as filling, aiming to create an asymmetric solid supercapacitor (ASC) device with compliable flexibility and high electrochemical performance. The effects of hydrothermal treatment and ice-template freezing parameters on electrochemical stability under repeated exterior deformation are discussed, the optimal parameters result in a high areal capacitance of 479.8 mF/cm2 in asymmetric supercapacitor device setup. The use of porous HGO and oriented GO aerogel synergistically contribute to the high energy and power density up to 1.69 Wh/m2 and 9 W/m2 as well as excellent electrochemical performance retention under repeated curving deformation which reaches 102% thanks to a novel activation process. The electrode assembly including metal foam and the buffering GO aerogel should be instructive for future supercapacitor design.

Hierarchical porous activated carbon derived from olives: Preparation, (N, S) co-doping, and its application in supercapacitors

For the structure and morphology of supercapacitor (SC) electrode materials, activation agent and processing technology are two important factors. Herein, we have developed an activated carbon material with high electrochemical performance obtained from olive husk, which is pre-treated by hydrothermal route followed activation treatment by dual activators. The effect of activation agents and heteroatom doping (N, S) on the structure and electrochemical performance of the obtained materials are deeply investigated. Optimized activation temperature at 700 °C was applied to create hierarchical porous carbon structure. The Olive husk-derived Activated Carbon with KOH/NaOH (OACKNa) has a specific surface area of 2900 m2·g−1, exhibits outstanding specific capacitance of 549 F·g−1 at 1 A·g−1 with high capacitance retention of 79.5% when the current density reaches up 30 A·g−1. Furthermore, OACKNa based symmetric SC device displays marvelous cyclic stability with rate capability of 93.2% after 10,000 cycles at 10 A·g−1. Interestingly, OACKNa device delivers high specific energy of 38.8 Wh·kg−1 even at ultrahigh specific power of 650 W·kg−1 at 1 A·g−1. Therefore, the obtained OACKNa with low-cost synthesis combined with the attractive electrochemical performances is a promising electrode material for supercapacitors.

Sugar beet pulp derived oxygen-rich porous carbons for supercapacitor applications

As a low-cost biomass, sugar beet pulp (SBP) was employed to prepare new activated porous carbons by microwave-assisted hydrothermal method followed by chemical activation with Mg(CH3COO)2⸱4H2O or ZnCl2 as activation agents. Various characterization techniques were employed to reveal the surface chemistry and morphology of the porous carbons. The porous carbons have micro and mesoporous structures according to the N2 adsorption-desorption isotherms and the highest specific surface area (SBET) was reached up to 950 m2/g. The oxygen content of porous carbons was proposed by elemental analysis and FT-IR spectroscopy. The oxygen-rich activated carbons exhibited very high methylene blue (MB) adsorption capacity up to 270.14 mg/g. The as-prepared activated sample exhibits high specific capacitance (263 F/g in 6 M KOH). A symmetric supercapacitor was assembled and researched in different electrolytes. The symmetric cell exhibited a high energy density of 21.8 Wh/kg at a power density of 449 W/kg and good capacitance retention of 77% over 10,000 cycles in 1 M Na2SO4 electrolyte. The high electrochemical performance of the SBP-derived porous carbons shows that they are highly promising for supercapacitor applications.

Synthesis and design of vanadium intercalated spinal ferrite (Co0.5Ni0.5VxFe1.6−xO4) electrodes for high current supercapacitor applications

Supercapacitors are promising energy storage systems as they offer low cost, high cyclic stability, and high-power density. However, at high currents, due to high voltage drops they show a consequent low energy density and irregular stability problems. Herein, we demonstrate a device that addresses these problems by vanadium-doped Co-Ni spinel ferrite nanoparticles (SFNP) (Co0.5Ni0.5VxFe2−xO4) where x = 0.00, 0.04, 0.08 and 0.10 into an activated carbon-based nanocomposite electrode. The fabricated supercapacitor device showed a successful energy density retention at high current without losing power density and cyclic stability. The device containing SFNPs based composite electrodes was achieved a specific energy of 57.24 Wh kg−1 at a specific power of 7.900 W kg−1 with excellent cyclic stability of 10,000 cycles. The prototype device was successfully powered RGB LED light. The low-cost production of materials and high electrochemical performance may pave the way for using these nanocomposites for highly stable energy storage devices.

Multiple reinforcement effect induced by gradient carbon coating to comprehensively promote lithium storage performance of Ti2Nb10O29

The synchronous improvement of ionic diffusivity and electronic conductivity of Ti2Nb10O29 (TNO) is of enormous significance for boosting its high electrochemical performance. In our work, a novel gradient carbon coating strategy was first proposed to synthesize the pomegranate-type N-doped carbon coated TNO microspheres (TNO@NPC), in which not only TNO microspheres but also TNO secondary nanoparticles surfaces are uniformly coated with an ultrathin carbon film. The study results demonstrate that such ingenious configuration can combine conductive coatings, nanocrystallization technology, and defect engineering together to greatly improve the ionic diffusivity and electronic conductivity. Moreover, the carbon coatings as the armor can effectively inhibit the volume change of TNO, and thus enhance its cycling durability. Density functional theory (DFT) calculations were also employed to illustrate the nature influence on lithium-ion diffusion coefficient and electronic conductivity. Attributing to the synergistic effect, the TNO@NPC exhibit superior rate capability (328 mA h g−1 at 0.1 C and 258 mA h g−1 at 10 C) and remarkable cyclability (210 mA h g−1 at 10 C after 1000 cycles) in half-cells. The full-cell of LiFePO||TNO@NPC also show notable rate capability (271 mA h g−1 at 0.2 C and 211 mA h g−1 at 10 C) and remarkable cyclability (178 mA h g−1 at 10 C after 1000 cycles). This ingenious structural design may provide a new direction for the construction of other high-quality electrodes in lithium-ion batteries (LIBs).

Double-shelled hybrid MgFe2O4/Fe2O3 hollow microspheres as a high-capacity anode for lithium-ion batteries

Ternary metal oxides Fe2O3 and MgFe2O4 have attracted considerable attention as lithium anode materials owing to their high theoretical capacities, environmental friendliness, and low cost; however, their rapid capacity decay and large volume expansion inhibit their lithium storage performance. Herein, we synthesize hybrid MgFe2O4/Fe2O3 hollow microspheres (MFO/FO-HS) hydrothermally, via the polyol reaction of ethylene glycol, followed by calcination at different temperatures. The surface morphology was tuned by adjusting the calcination temperature, assisted by inward and outward Ostwald ripening. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis were performed to investigate the physio-chemical properties of the prepared samples. The sample calcined at 450 °C exhibited an excellent electrochemical performance and retained a reversible capacity of 1390 mAh g−1 after 160 cycles, indicating the significant role of calcination temperature in tuning the structural and electrochemical properties of anode materials. The double-shelled hollow microspheres inhibit rapid capacity decay and prevent severe volume expansion during the electrochemical process. This work opens new paths toward constructing an electrode material with a high electrochemical performance.

Metal ion-assisted conversion of Co-ZIF-L to CoNi-layered double hydroxides with high electrochemical properties for supercapacitors

Metal ion-induced etching can effectively convert zeolitic imidazolate frameworks (ZIFs) to CoNi-layered double hydroxides (LDH). Here, different metal-ion-assisted etching methods are utilized to convert Co-ZIF-L to CoNi-LDH with various morphologies and electrochemical properties. The resultant CoNi-LDH (CoNi-1) with a composition of Co0.7Ni0.3(OH)2 displayed a high electrochemical performance when Co-ZIF-L was treated in N, N-dimethylformamide-ethanol solution containing Co2+ ions followed by Ni2+ ion-induced etching under hydrothermal condition. The improved electrochemical performance of CoNi-1 can be attributed to structural advantages, where the well-dispersed ultrathin CoNi-LDH layers favor the exposure of surface active sites and promote ion diffusion to maximize electrochemical properties.

One-step electrodeposition of a polypyrrole/NiO nanocomposite as a supercapacitor electrode

An electrochemical deposition technique was used to fabricate polypyrrole (Ppy)/NiO nanocomposite electrodes for supercapacitors. The nanocomposite electrodes were characterized and investigated by Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS). The performance of supercapacitor electrodes of Ppy/NiO nanocomposite was enhanced compared with pristine Ppy electrode. It was found that the Ppy/NiO electrode electrodeposited at 4 A/cm−2 demonstrated the highest specific capacitance of 679 Fg−1 at 1 Ag−1 with an energy density of 94.4 Wh kg−1 and power density of 500.74 W kg−1. Capacitance retention of 83.9% of its initial capacitance after 1000 cycles at 1 Ag−1 was obtained. The high electrochemical performance of Ppy/NiO was due to the synergistic effect of NiO and Ppy, where a rich pores network-like structure made the electrolyte ions more easily accessible for Faradic reactions. This work provided a simple approach for preparing organic–inorganic composite materials as high-performance electrode materials for electrochemical supercapacitors.

Electrodeposition synthesis of high performance MoO3-x@Ni-Co layered double hydroxide hierarchical nanorod arrays for flexible solid-state supercapacitors

• The design of hierarchical structure can effectively improve the electrochemical performance of MoO 3. • Oxygen defect production can effectively improve the conductivity of MoO 3 . • MoO 3-x @NCLDH-15 symmetric flexible SSCs exhibits high energy density and power density. As a pseudocapacitive material, layered MoO 3 has attracted extensive attention for its excellent ion storage capacity. However, the low conductivity and irreversible phase transition make its capacity decrease rapidly during the charging and discharging process, which seriously limits the application in the field of supercapacitors. This study obtains the hierarchical MoO 3-x @NCLDH with oxygen vacancy by using the MoO 3 nanorods array as the matrix, wrapping the Ni-Co layered double hydroxide (NCLDH) by electrodeposition method. The MoO 3-x @NCLDH-15 electrode with the electrodeposition time of 15 min shows a capacitance of 3.49 F cm −2 at the current density of 5 mA cm −2 and capacitance retention of 94.5% after 3000 cycles in the neutral electrolyte. The prepared symmetric flexible solid-state supercapacitor with MoO 3-x @NCLDH-15 as electrode material exhibits good flexibility and the maximum energy density of 0.047 mWh cm −2 at 0.865 mW cm −2 power density. On the one hand, the hierarchical structure changes the microenvironments of the electrode surface, which can provide more responsive sites for pseudocapacitance reaction and shorten the ion transportation path to accelerate the reaction kinetics. On the other hand, NCLDH nanosheets tightly wrapped on the surface of MoO 3 nanorods array slow down the structural collapse in the potassium ion removal process. Besides, the introduction of oxygen vacancies improves the electrical conductivity and structural stability of MoO 3 . Therefore, our work provides a new strategy for constructing flexible electrode materials with high electrochemical performance.