Superb Rate Capability Research Articles

High-value conversion of invasive plant into nitrogen-doped porous carbons for high-performance supercapacitors

Given the harm caused by invasive plants to the environment and the high cost of treatment, we propose high-value transformation and utilization for invasive plants. Highly porous carbon derived from invasive plant (Canada goldenrod) was successfully synthesized through a feasible and green carbonization approach, which was firstly utilized as supercapacitor electrode. It is found that the addition of nitrogen (N)-rich chlorella could positively increase the N content and considerably boost the specific surface area up to 2231.41 m2 g-1 for the resultant Carbon-GC1-800, which are crucial factors for accelerating the ion transport and improving the capacitive behaviors. Notably, Carbon-GC1-800 exhibits the highest ratio (70.9%) of microporous volume to total pore volume. The electrochemical properties of Carbon-GC1-800 electrode exhibits an outstanding specific capacitance of 388.2Fg-1 at a current density of 0.5Ag-1 and a superb rate capability of 75.7% from 0.5Ag-1 to 10Ag-1. The assembled symmetric supercapacitor with ionic liquid as electrolyte demonstrates the exceptional maximum power density of 8753.7Wkg-1 and peak energy density of 59.3Whkg-1. This study presents the novel ideas and effective techniques to produce porous carbons for energy storage from invasive plant resources.

Mesoporous hollow Fe4[Fe(CN)6)]3 hierarchical nanocrystal architecture for advanced sodium-ion batteries

Prussian blue (PB) has been broadly recognized as promising cathode materials for sodium-ion batteries (SIBs) due to its large interstitial space and robust frame structure, whereas their applications are impeded by unsatisfied long-term cyclability and poor rate capability due to its inherent lattice defects. Herein, we report to fabricate the mesoporous hollow Fe4(Fe(CN)6)3 (one kind of PB) hierarchical nanocrystal architecture by the hydrothermal crystallization and HCl etching of the mesoporous precursor Fe4[Fe(CN)6]3 cubic particles, leading to high crystallinity and large specific surface area. The resultant Fe4[Fe(CN)6]3 cathode for SIBs exhibits a good reversibility and cycling stability with a capacity retention of 75.6 % at 0.5 C after 200 cycles as well as superb rate capability featuring a stable discharge specific capacity of 30.2 mAh g−1 at as high as 10 C, demonstrating the fast kinetics and low polarization of electrochemical reaction, which might be ascribed to the unique architecture and high crystallinity. This offers a new route to designing PB cathode of for SIBs with high rate capabilities.

Medium-mediated high-crystalline Prussian blue toward exceptionally boosted sodium energy storage

Prussian blue and its analogues (PB/PBAs) represent a promising community of low cost and high capacity cathode materials for sodium ion batteries. Nevertheless, the synthesis-induced crystal deficiencies in the framework of PB/PBAs greatly degrade their sodium energy properties, which challenges the potential practicability. Herein, we demonstrate an effective strategy to regulate the PB crystallinity with advanced sodium energy by tuning the synthesis medium. A favorable agent of sodium polyacrylate is screened out as the reaction mediator, which creates a strong coordinating and highly viscous environment to produce high-crystalline PB (HC-PB). Remarkably, the HC-PB harvests an elevated capacity of 140 mAh g–1 at 0.2 C, superb rate capability (105 mAh g–1 at 30 C), and prominent capacity retention of 94.6 % over 1000 cycles at 10 C. The combination of in situ mechanistic and kinetic analyses reveals the rooting reasons for the performance enhancement. This study opens up a prospective and feasible medium-mediated pathway to accelerate the development of PB/PBAs toward sodium chemistry and beyond.

Zero-Strain Sodium Lanthanum Titanate Perovskite Embedded in Flexible Carbon Fibers as a Long-Span Anode for Lithium-Ion Batteries.

"High-capacity" graphite and "zero-strain" spinel Li4Ti5O12 (LTO) occupy the majority market of anode materials for Li+ storage in commercial applications. Nevertheless, their intrinsic drawbacks including the unsafe potential of graphite and unsatisfactory capacity of LTO limit the further development of lithium-ion batteries (LIBs), which is unable to satisfy the ever-increasing demands. Here, a novel Na0.35La0.55TiO3 perovskite embedded in multichannel carbon fibers (NLTO-NF) is rationally designed and synthesized through an electrospinning method. It not only has the advantages of a respectable specific capacity of 265 mAh g-1 at 0.1 A g-1 and superb rate capability, but it also possesses the zero-strain characteristic. Impressively, an ultralong cycling life with 96.3% capacity retention after 9000 cycles at 2 A g-1 is achieved in the half cell, and 90.3% of capacity retention ratio is obtained after even 2500 cycles at 1 A g-1 in the coupled LiFePO4/NLTO-NF full cell. This study introduces a new member with excellent performance to the zero-strain materials family for next-generation LIBs.

Stress Dissipation Driven by Multi-Interface Built-In Electric Fields and Desert-Rose-Like Structure for Ultrafast and Superior Long-Term Sodium Ion Storage.

The kinetics and durability of conversion-based anodes greatly depend on the intrinsic stress regulating ability of the electrode materials, which has been significantly neglected. Herein, a stress dissipation strategy driven by multi-interface built-in electric fields (BEFs) and architected structure, is innovatively proposed to design ultrafast and long-term sodium ion storage anodes. Binary Mo/Fe sulfide heterostructured nanorods with multi-interface BEFs and staggered cantilever configuration are fabricated to prove our concept. Multi-physics simulations and experimental results confirm that the inner stress in multiple directions can be dissipated by the multi-interface BEFs at the micro-scale, and by the staggered cantilever structure at the macro-scale, respectively. As a result, our designed heterostructured nanorods anode exhibits superb rate capability (332.8 mAh g-1 at 10.0 A g-1 ) and durable cyclic stability over 900 cycles at 5.0 A g-1 , outperforming other metal chalcogenides. This proposed stress dissipation strategy offers a new insight for developing stable structures for conversion-based anodes.

Stress Dissipation Driven by Multi‐Interface Built‐In Electric Fields and Desert‐Rose‐Like Structure for Ultrafast and Superior Long‐Term Sodium Ion Storage

AbstractThe kinetics and durability of conversion‐based anodes greatly depend on the intrinsic stress regulating ability of the electrode materials, which has been significantly neglected. Herein, a stress dissipation strategy driven by multi‐interface built‐in electric fields (BEFs) and architected structure, is innovatively proposed to design ultrafast and long‐term sodium ion storage anodes. Binary Mo/Fe sulfide heterostructured nanorods with multi‐interface BEFs and staggered cantilever configuration are fabricated to prove our concept. Multi‐physics simulations and experimental results confirm that the inner stress in multiple directions can be dissipated by the multi‐interface BEFs at the micro‐scale, and by the staggered cantilever structure at the macro‐scale, respectively. As a result, our designed heterostructured nanorods anode exhibits superb rate capability (332.8 mAh g−1 at 10.0 A g−1) and durable cyclic stability over 900 cycles at 5.0 A g−1, outperforming other metal chalcogenides. This proposed stress dissipation strategy offers a new insight for developing stable structures for conversion‐based anodes.

Binder-free barium-implanted MnO2 nanosheets on carbon cloth for flexible zinc-ion batteries.

The intrinsically low electrical conductivity and poor structural fragility of MnO2 have significantly hampered the zinc storage performance. In this work, Ba2+-implanted δ-MnO2 nanosheets have been hydrothermally grown on a carbon cloth (Ba-MnO2@CC) as an extremely stable and efficient cathode material of aqueous zinc-ion batteries. The three-dimensionally porous architecture composed of interwoven thin MnO2 nanosheets effectively shortens the electron/ion transport distances, enlarges the electrode/electrolyte contact area, and increases the active sites for the electrochemical reaction. Meanwhile, Ba2+ could function as an interlayer pillar to stabilize the crystal structure of MnO2. Consequently, the as-optimized Ba-MnO2@CC exhibits remarkable Zn2+ storage capabilities, such as a high capacity (305 mAh g-1 at 0.2Ag-1), prolonged lifespan (95% retention after a 200-cycling test), and superb rate capability. The binder-free cathode is also applicable for flexible energy storage devices with attractive properties. The present investigation provides important insights into designing advanced cathode materials toward wearable electronics.

Iron-doped nickel–cobalt bimetallic phosphide nanowire hybrids for solid-state supercapacitors with excellent electromagnetic interference shielding

The development of flexible and wearable electronics subjects to the limited energy density and accompanying electromagnetic pollution. With a high theoretical specific capacity, nickel–cobalt bimetallic phosphide (NiCoP) is considered to be potential cathode materials for supercapacitor. However, the pristine NiCoP fails to display excellent electrochemical performance due to its inferior rate performance and cycling stability. Herein, we design Fe doped NiCoP nanowire arrays on carbon cloth (Fe-NiCoP/CC) as the cathode for supercapacitors. The introduced Fe doping enable to increase in the electronic conductivity and enhance the adsorption of OH−, supported by the density functional theory (DFT) analysis. As a result, Fe-NiCoP/CC electrode displays a high areal capacity of 3.18 F cm−2 at 1 mA cm−2, superb rate capability (86.3 % capacity retention at 20 mA cm−2) and outstanding structure stability, superior to the NiCo/CC, FeNiCo/CC, and NiCoP/CC counterparts. Moreover, the assembled Fe-NiCoP/CC||VN/CNT/CC hybrid supercapacitor (HSC) device delivers a high energy density of 176.9 μWh cm−2 at the power density of 750 μW cm−2. More importantly, the designed electrodes and assembled HSC device exhibits excellent electromagnetic interference (EMI) shielding performance. This design concept presented in this paper can provide insights into the construction of multifunctional and high-performance flexible electronic devices.

Solvent triggering assembly of self-supported MXene hydrogel for high performance asymmetric supercapacitors

Constructing 3D porous structure of MXene (Ti3C2Tx) is an efficient approach to prevent nanosheets restacking and realize prominent electrochemical functionality. However, the assembly of self-supported 3D Ti3C2Tx architecture is difficult due to the inherent rigidity and superior hydrophilicity of Ti3C2Tx nanosheets. Herein, a solvent-triggering gelation strategy is developed using polar aprotic N,N-Dimethylformamide and polar protic H2O as co-solvent to enhance hydrogen bonding and Ti-O-Ti covalent bonding between Ti3C2Tx nanosheets. Thereby, self-supported Ti3C2Tx hydrogel (MH12/5:5) in absence of any crosslinkers or substrates has been successfully fabricated. The MH12/5:5 hydrogel exhibits excellent specific capacitance of 384.4 F g1 and superb rate capability of 61 % in a broad current density range of 1–100 A g−1. Asymmetric supercapacitor has been assembled using MH12/5:5 hydrogel as negative electrode and a polyaniline hydrogel as positive electrode, which presents high energy density of 21.2 Wh kg−1. This solvent-triggering gelation strategy points toward a promising direction to develop self-supported MXene hydrogels for high performance energy storage devices.

Engineering conductive and catalytic triple-phase interfaces for high efficiency polysulfides conversion in Li-S batteries

The well-known shuttle effect of lithium polysulfides (LiPSs) in the ether-based liquid electrolyte and polymer solid electrolytes are the main roadblocks of Li-S batteries to perform high discharge capacity with a long cycling lifespan. Herein, a triple phase interface among carbon/catalysts (vanadium single atoms (VSAs) and metallic cobalt nanoparticles (CoNPs))/electrolyte is proposed for the high-performance Li-S batteries. At the triple-phase interfaces, the LiPSs are chemically immobilized and electrocatalytically transformed into insoluble Li2S at the rate-determining process of liquid–solid conversion. The nucleation and growth of Li2S precipitates were dominated by the interface chemistry and the dispersion of catalysts (3D reconstruction image). In the Li-S batteries with liquid ether-based electrolytes, a discharge capacity of 1343 mAh g−1 was achieved at 0.1 C and the decay of capacity was decelerated with 0.05% per cycle for 500 cycles at 1 C, as well as superb rate capability (808 mAh·g−1 at 5 C). The triple phase interfaces also exhibited high performance in solid state Li-S batteries with solid polymer electrolytes, which the discharge capacity reaches 1289 mAh·g−1 at 0.05 C and 849 mAh·g−1 at 0.5 C.

Toward Highly Selective Heteroatom Dopants in Hard Carbon with Superior Lithium Storage Performance.

Hard carbons (HCs) have gained much attention for next-generation high energy density lithium-ion battery (LIB) anode candidates. However, voltage hysteresis, low rate capability, and large initial irreversible capacity severely affect their booming application. Herein, a general strategy is reported to fabricate heterogeneous atom (N/S/P/Se)-doped HC anodes with superb rate capability and cyclic stability based on a three-dimensional (3D) framework and a hierarchical porous structure. The obtained N-doped hard carbon (NHC) exhibits an excellent rate capability of 315 mA h g-1 at 10.0 A g-1 and a long-term cyclic stability of 90.3% capacity retention after 1000 cycles at 3 A g-1. Moreover, the as-constructed pouch cell delivers a high energy density of 483.8 W h kg-1 and fast charging capability. The underlying mechanisms of lithium storage are illustrated by electrochemical kinetic analysis and theoretical calculations. It is demonstrated that heteroatom doping imposes significant effects on adsorption and diffusion for Li+. The versatile strategy in this work opens an avenue for rational design of advanced carbonaceous materials with high performance for LIB applications.

N-functionalization and defect engineering in ZnCo2O4 nanosheets boosted the performance of Zn-ion hybrid supercapacitor

Transition-metal oxides are a class of promising pseudocapacitive materials for high energy density supercapacitors, while their low intrinsic conductivity and remarkable volume expansion deteriorate the electrochemical properties. Herein, we develop a binder-free mesoporous architecture supported on a carbon cloth (CC) substrate based on the nitrogen (N)-doped and oxygen vacancy (Ov)-rich zinc cobalt oxide nanosheets (denoted by N-Ov-ZCO@CC). Because of the instructive synergy of doping, defect, and surface engineering achieved by N-functionalization, the N-Ov-ZCO@CC exhibits significantly enhanced electrochemical properties. The N-Ov-ZCO@CC single electrode exhibited a high capacitance of 2166.4 F/g at 1 A/g with superb rate-capability (91.2% at 20 A/g) and superior cycling stability of 98.99% up to 5,000 cycles. In addition, a zinc-ion hybrid supercapacitor (ZHSC) device, assembled with the N-Ov-ZCO@CC as the cathode and Zn-foil as the anode, shows a high energy density of 95.35 Wh/kg at the power density of 10,008 W/kg, superior to most state-of-the-art ZHSCs. This work provides an effective strategy for constructing multifunctional electrochemical energy materials for ZHSCs.

Directly-regenerated LiCoO2 with a superb cycling stability at 4.6 V

The exponential growth of “3C” (computer, communication, and consumer electronics) market generates an ever-increasing demand on recycling materials from the end-of-life LiCoO2 (LCO) batteries with ecological and efficient methods. Herein, we present a direct and scalable approach to recycle the degraded LCO by healing and stabilizing their damaged structure via solid reactions. The as-proposed approach constructs a protective layer onto the regenerated LCO particles to suppress the O3 to H1–3 phase transition at 4.55 V. Benefiting from the unique design, superb electrochemical performance was achieved for the regenerated LCO, exhibiting a high specific capacity retention of 85.9% after 100 cycles with a charging cut-off voltage of 4.6 V and a superb rate capability, which are even superior to those of the pristine commercial LCO. In addition, compared with the LCO production with raw chemicals, the as-proposed healing-stabilizing strategy reduces the total energy consumption by 68.5%, bringing noteworthy economic and environmental benefits. This work provides not only new understandings to stabilize LCO at high voltage, but also a practical solution to the closed-loop development of LCO batteries.

High-Energy Sn-Ni and Sn-Air Aqueous Batteries via Stannite-Ion Electrochemistry.

Tin is promising for aqueous batteries (ABs) due to its multiple electrons' reactions, high corrosion resistance, large hydrogen overpotential, and excellent environmental compatibility. However, restricted to the high thermodynamic barrier and the poor electrochemical kinetics, efficient alkaline Sn plating/stripping at facile conditions has not yet been realized. Here, for the first time, we demonstrate a highly reversible stannite-ion electrochemistry and construct a novel paradigm of high-energy Sn-based ABs. Combined spectroscopic characterization, electrochemical evaluation, and theoretical computation reveal the thermodynamic merits with a low reaction energy barrier and feasible H2O participation in Sn-ion reduction as well as the kinetic merits with fastened surface charge transfer and SnO22- diffusion. The resultant alkaline Sn anode delivers a low potential of -1.07 V vs Hg/HgO, a specific capacity of 450 mA h g-1, a Coulombic efficiency of near 100%, superb rate capability at 45.5 A g-1, and excellent cycling durability without dendrite and dead Sn. As a proof of concept, we developed new high-energy Sn-based ABs, including 1.45 V Sn-Ni with 314 W h kg-1 (58 kW kg-1 and over 15,000 cycles) and 1.0 V Sn-air with 420 W h kg-1 (lifespan over 1900 h), on the basis of masses from cathode and anode active materials. The findings prove the feasibility of the alkaline Sn metal anode, and the new suite of high-energy Sn-based ABs may be of immediate benefit toward safe, reliable, and affordable energy storage.

A hydrogel-assisting surface-confined corrosion strategy toward self-supported amorphous NiFe-layered double hydroxides enabling high-performance hybrid solid-state supercapacitors

Layered double hydroxides (LDHs) are promising energy materials for supercapacitors. It is demonstrated that the integrated performance of the amorphous LDHs is superior to that of crystalline materials. However, it is still a great obstacle to producing amorphous LDHs. Herein, a simple and facile strategy is proposed to synthesize the self-supported amorphous NiFe-LDHs using a surface-confined method. The corrosion process takes place in a cost-effective hydrogel at ambient temperature and pressure, which can synchronously change the chemical structure and morphology of the NiFe-LDHs. This method is also proved to be effective in fabricating S-doped amorphous NiFe-LDHs. The as-prepared products show excellent electrochemical performance in the charge-discharge process with fast kinetics, low impedance, good stability, and significant capacity, which is superior to most reported crystalline electrode materials. Moreover, the assembled hybrid solid-state supercapacitor devices display excellent capacitive performance including high energy density, superb rate capability and outstanding long-term cycling stability. This work offers a new sight into economically synthesizing amorphous mixed-metal compositions for high-performance supercapacitors.

Quasi-solid-state hybrid supercapacitors assembled by Ni-Co-P@C/Ni-B nanoarrays and porous carbon nanofibers with N-doped C nanocages

In recent times, a lot of research effort has been performed to develop hybrid supercapacitors (HSCs) because of their ability to produce high energy density as well as superb power density. The key issue for realizing high-performance HSCs is to minimize the kinetic mismatch between rapid capacitor-type anode and sluggish battery-type cathode. Optimizing the interface, morphology and microstructure of the electrode material is a favorable approach to surmount kinetic imbalance. Herein, a core–shell nanoarrays of ultrathin carbon layer-coated crystalline Ni-Co-phosphide (Ni-Co-P@C) and amorphous Ni-boride (Ni-B) is fabricated on a nickel foam substrate as a positive electrode material (Ni-Co-P@C/Ni-B). Theoretical analyses validate the best metallic characteristic and most stable OH* absorption energy for Ni-Co-P@C/Ni-B, which enhance its charge storage performance than analogous Ni-Co-P and Ni-Co-P/Ni-B. The porous nitrogen (N)-doped carbon (C) nanofibers consisting of tightly embedded metal–organic framework (ZIF-8)-derived interconnected N-C nanocages (HP-N-CFs) showed excellent charge storage kinetics as a negative electrode. The battery-type Ni-Co-P@C/Ni-B electrode revealed a specific capacity of 306.2 mA h g−1 at 3 mA cm−2, while highly porous capacitive HP-N-CFs electrode showed the highest capacity of 56 mA h g−1 at 2.5 mA cm−2. In addition, the assembled quasi-solid-state (Ni-Co-P@C/Ni-B//HP-N-CFs) HSCs exhibited the highest energy density of 68.3 W h kg−1 at a power density of 472 W kg−1 with a superb rate capability (68% at 50 mA cm−2) and decent cyclic durability (90% retention over 10,000 cycles).

Superb high voltage performance of LiCoO2 with structure and surface highly stabilized by co-doping trace Mg and F during one-pot solid-state synthesis

Superior high voltage performance of LiCoO2 (LCO) is rarely achieved due to severe structure destruction and side reactions at high voltage. Here, a facile solid-state-reaction strategy via co-doping trace Mg and F ions using MgO and LiF sources is proposed. Trace Mg and F co-doped LCO (LCO-MF) achieves superb rate capability and long-term cycling stability both in half and full cells, such as a capacity of 124 mAh/g at 20 C (1 C = 280 mA/g), a capacity retention of 80.8% after 500 cycles at 4.6 V (1 C) in half cell, and a capacity retention of 92.3% after 2200 cycles at 4.5 V (1 C) in full cell. Mg predominantly pillars and stabilizes the Li channels to promote Li+ transport and phase transitions effectively, especially at high voltages, and F weakens the oxygen repulsion to improve electronic conduction and suppresses the release of oxygen and thus stabilizes the surface, which synergistically stabilizes structure and surface effectively. The strategy of simultaneously enhancing structure reversibility and stabilizing surface for performance improvement of LCO via co-doping and optimizing trace dual cations and anions during one-pot solid-state synthesis is suitable for mass production.

Metal Chelation Enables High-Performance Tea Polyphenol Electrodes for Lithium-Ion Batteries

The application of organic electrode materials can make the whole cycle of the lithium battery operation effective for green sustainability. However, poor electronic conductivity and strong solubility in nonprotonic electrolytes limit the application of organic anodes. Here, a novel organic anode material, TP-Ni, was fabricated through the simple chelation of tea polyphenols with nickel ions. Benefiting from coordination bonds that alter the intrinsic microstructure of TPs and contribute to pseudocapacitive charging, the TP-Ni anode exhibits remarkable electrochemical properties, including a high specific capacity (1163 mAh g−1 at 0.1 A g−1), superb rate capability, and extraordinary cycling stability (5.0 A g−1 over 4000 cycles with a capacity retention of 87.8%). This work can provide guidance for the design and synthesis of new high-performance organic electrode materials in the future and help accelerate the process of organic electrode material applications.

Construction of strong built-in electric field in binary metal sulfide heterojunction to propel high-loading lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries is greatly hindered by soluble polysulfides shuttling and sluggish sulfur redox kinetics. Rational design of multifunctional hybrid materials with superior electronic conductivity and high electrocatalytic activity, e.g., heterostructures, is a promising strategy to solve the above obstacles. Herein, a binary metal sulfide MnS-MoS2 heterojunction electrocatalyst is first designed for the construction of high-sulfur-loaded and durable Li-S batteries. The MnS-MoS2 p-n heterojunction shows a unique structure of MoS2 nanosheets decorated with ample MnS nanodots, which contributes to the formation of a strong built-in electric field at the two-phase interface. The MnS-MoS2 hybrid host shows strong soluble polysulfide affinity, enhanced electronic conductivity, and exceptional catalytic effect on sulfur reduction. Benefiting from the synergistic effect, the as-derived S/MnS-MoS2 cathode delivers a superb rate capability (643 mA h g−1 at 6 C) and a durable cyclability (0.048% decay per cycle over 1000 cycles). More impressively, an areal capacity of 9.9 mA h cm−2 can be achieved even under an extremely high sulfur loading of 14.7 mg cm−2 and a low electrolyte to sulfur ratio of 2.9 μL mg−1. This work provides an in-depth understanding of the interfacial catalytic effect of binary metal compound heterojunctions on sulfur reaction kinetics.

Uniformly confined V2O3 quantum dots embedded in biomass derived mesoporous carbon toward fast and stable energy storage

Rational composition and structural design of electrode substances are critical for lithium-ion batteries (LIBs) and supercapacitors (SCs) with good cycling steadiness and superb rate capability. Therefore, we report a novel electrode material consisting of V2O3 quantum dots (QDs, about 6.64 nm) well-distributed on mesoporous carbon (MC) nanosheets. V2O3 has high intrinsic conductivity and an open tunnel-like lattice structure, facilitating electron transfer and ion intercalation. The composite architectures can offer more electrochemical active sites, shorten ion/electron diffusion paths, and reduce volume swings during the charging/discharging process. The synergic effect of these merits significantly improves the reaction kinetics and prevents structural damage to the entire electrode. As a result, V2O3-QDs/MC nanosheets exhibit a large capacity/capacitance, excellent cycling steadiness, and high rate performance. For LIBs, V2O3-QDs/MC displays a great reversible capacity of 931 mAh g−1 at 0.2 A g−1 over 500 cycles and fast and stable lithium storage behaviors with 822 mAh g−1 at 2 A g−1 after 1000 cycles. For SCs, V2O3-QDs/MC manifests a considerable specific capacitance of 270 F g−1 at 1 A g−1 and satisfactory durability for at least 5000 cycles at 10 A g−1. This work informs a good structure design for constructing advanced metal oxide-based nanostructured electrode materials.