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Electrochemical proton storage provides high energy, fast kinetics, safety, and environmental friendliness for grid‐scale energy storage. However, the development of pseudocapacitive proton supercapacitors with fast chargeability and high stability is still challenging because of the unclear electrochemical reaction mechanism and unsuitable construction strategy. Here it is shown that a multi‐metallic Prussian blue analog—Cu0.82Co0.18HCF, which possesses enhanced electronic structure and ion transport path—can intercalate/de‐intercalate large amounts of proton at high rates. Ion‐induced transformation of magnetism, fast solid‐state proton transport, and reversible insertion/de‐insertion of protons lead to extremely excellent rate capacities and cycling stability for proton storage. An asymmetric pseudocapacitive proton supercapacitor (Cu0.82Co0.18HCF//WO3·nH2O) is fabricated with a voltage window of 1.7 V, delivering a maximum energy density of 35 Wh kg−1 and an energy density of 22 Wh kg−1 at a high power density of 26 kW kg−1. Combining systematical material design and mechanism study, this work not only broadens the preparation of electrode materials but also brings light to the construction of high‐performance devices for efficient proton storage. [ABSTRACT FROM AUTHOR]

Zinc‐ion batteries (ZIBs) have been regarded as one of the most promising aqueous energy storage devices due to their low‐cost, high capacity, and intrinsic safety. However, the relatively low Coulombic efficiency caused by the dendrite formation and side reactions greatly hinders the rejuvenation of ZIBs. Here, an utterly simple approach by pencil drawing is employed to improve the poor performance of normal Zn anode and hinders the formation of passivated byproduct as well as serious dendrite growth. Significantly, the functional graphite layer can not only act as ions buffer, but also guide the uniform nucleation of Zn2+ in graphite voids. With such synergy effect, the graphite‐coated Zn anode (Zn–G) displays low overpotential, high reversibility, and dendrite‐free durability compared with the pristine Zn. Consequently, a low voltage hysteresis of ≈28 mV can be achieved and maintained over 200 h. Furthermore, the Zn–G anode is paired with a V2O5·xH2O cathode to construct a rechargeable ZIB. As‐assembled device can output high energy/power density of 324.3 Wh kg−1/3269.8 W kg−1 (based on the active mass loading in cathode) together with a capacity retention of ≈84% over 1500 cycles at a current density of 5 A g−1. [ABSTRACT FROM AUTHOR]

Abstract: Highly conductive metal selenides are gaining prominence as promising electrode materials in electrochemical energy‐storage fields. However, phase‐pure bimetallic selenides are scarcely retrieved, and their underlying charge‐storage mechanisms are still far from clear. Here, first a solvothermal strategy is devised to purposefully fabricate monodisperse hollow NiCoSe2 (H‐NiCoSe2) sub‐microspheres. Inherent formation of metallic H‐NiCoSe2 is tentatively put forward with comparative structure‐evolution investigations. Interestingly, the fresh H‐NiCoSe2 does not demonstrate striking supercapacitive behaviors when evaluated for electrochemical supercapacitors (ESs). But it exhibits competitive pseudocapacitance of ≈750 F g−1 at a rate of 3 A g−1 with a high loading of 7 mg cm−2 after ≈100 cyclic voltammetry (CV) cycles. With systematic physicochemical/electrochemical analyses, intrinsic energy‐storage mechanism of the H‐NiCoSe2 is convincingly revealed that the electrooxidation‐generated biactive CoOOH/NiOOH phases in aqueous KOH over CV scanning, rather than the H‐NiCoSe2 itself, account for the remarkable pesudocapacitance observed after cycling. An assembled H‐NiCoSe2‐based asymmetric device has delivered an energy density of ≈25.5 Wh kg−1 with a power rate of ≈3.75 kW kg−1, and long‐span cycle life. More significantly, the electrode design and new perspectives here hold profound promise in enriching material synthesis methodologies and in‐depth understanding of the complex charge‐storage process of newly emerging pseudocapacitive materials for next‐generation ESs. [ABSTRACT FROM AUTHOR]

Abstract: Spinel LiNi0.45Cr0.1Mn1.45O4 synthesized by a scalable solution route combined by high temperature calcination is investigated as cathode for ultralong‐life lithium‐ion batteries in a wide operating temperature range. Scanning electron microscopy reveals homogeneous microsized polyhedral morphology with highly exposed {100} and {111} surfaces. The most highlighted result is that LiNi0.45Cr0.1Mn1.45O4 has extremely long cycle performance and high capacity retention at various temperatures (0, 25, 50 °C), indicating that Cr doping is a prospective approach to enable 5 V LiNi0.5Mn1.5O4 (LNMO)‐based cathode materials with excellent cycling performances for commercial applications. After 1000 cycles, the capacity retention of LiNi0.45Cr0.1Mn1.45O4 is 100.30% and 82.75% at 0 °C and 25 °C at 1 C rate, respectively. Notably, over 350 cycles at 50 °C, the capacity retention of LiNi0.45Cr0.1Mn1.45O4 can maintain up to 91.49% at 1 C. All the values are comparable to pristine LNMO, which can be attributed to the elimination of LiyNi1−yO impurity phase, highly exposed {100} surfaces, less Mn3+ ions, and enhancement of ion and electron conductivity by Cr doping. Furthermore, an assembled LiNi0.45Cr0.1Mn1.45O4/Li4Ti5O12 full cell delivers an initial discharge capacity of 101 mA h g−1, meanwhile the capacity retention is 82.07% after 100 cycles. [ABSTRACT FROM AUTHOR]

Versatile bioinspired strategies are urgently needed to fabricate high-performance nanoprobes for biomedical application. Herein, a novel bioinspired technology of mimicking drug-substrate interaction is reported for the fabrication of high-performance nanoprobes. As a proof of concept, a multifunctional bovine serum albumin (BSA)-MnO2 nanoparticle-based nanoplatform is strategically engineered via mimicking the disinfection process of KMnO4 in an extremely facile way. The prepared BSA-MnO2 nanoparticles possess sub-10 nm and uniform size, excellent colloidal stability, and impressive T1 relaxivity of 7.9 m m−1 s−1. The proposed nanoprobe could not only be employed as a high-performance magnetic resonance imaging (MRI) agent for tumor and renal imaging but can also provide a platform for integrating therapeutic strategies toward tumors. The universal strategy could also be easily extended to the fabrication of other nanoprobes for MR imaging in vivo using other bioactive proteins including ovalbumin and transferrin. This work will open a new way for the development of biomaterials in biomedicine applications. [ABSTRACT FROM AUTHOR]

Flexible energy storage devices are critical components for emerging flexible and wearable electronics. Improving the electrochemical performance of flexible energy storage devices depends largely on development of novel electrode architectures and new systems. Here, a new class of flexible energy storage device called flexible sodium-ion pseudocapacitors is developed based on 3D-flexible Na2Ti3O7 nanosheet arrays/carbon textiles (NTO/CT) as anode and flexible reduced graphene oxide film (GFs) as cathode without metal current collectors or conducting additives. The NTO/CT anode with advanced electrode architectures is fabricated by directly growing Na2Ti3O7 nanosheet arrays on carbon textiles with robust adhesion through a simple hydrothermal process. The flexible GF//NTO/CT configuration achieves a high energy density of 55 Wh kg−1 and high power density of 3000 W kg−1. Taking the fully packaged flexible sodium-ion pseudocapacitors into consideration, the maximum practical volumetric energy density and power density reach up to 1.3 mWh cm−3 and 70 mW cm−3, respectively. In addition, the flexible GF//NTO/CT device demonstrates a stable electrochemical performances with almost 100% capacitance retention under harsh mechanical deformation. [ABSTRACT FROM AUTHOR]

In the work, a facile yet efficient self-sacrifice strategy is smartly developed to scalably fabricate hierarchical mesoporous bi-component-active ZnO/ZnFe2O4 (ZZFO) sub-microcubes (SMCs) by calcination of single-resource Prussian blue analogue of Zn3[Fe(CN)6]2 cubes. The hybrid ZZFO SCMs are homogeneously constructed from well-dispersed nanocrstalline ZnO and ZnFe2O4 (ZFO) subunites at the nanoscale. After selectively etching of ZnO nanodomains from the hybrid, porously assembled ZFO SMCs with integrate architecture are obtained accordingly. When evaluated as anodes for LIBs, both hybrid ZZFO and ZFO samples exhibit appealing electrochemical performance. However, the as-synthesized ZZFO SMCs demonstrate even better electrochemical Li-storage performance, including even larger initial discharge capacity and reversible capacity, higher rate behavior and better cycling performance, particularly at high rates, compared with the single ZFO, which should be attributed to its unique microstructure characteristics and striking synergistic effect between the bi-component-active, well-dispersed ZnO and ZFO nanophases. Of great significance, light is shed upon the insights into the correlation between the electrochemical Li-storage property and the structure/component of the hybrid ZZFO SMCs, thus, it is strongly envisioned that the elegant design concept of the hybrid holds great promise for the efficient synthesis of advanced yet low-cost anodes for next-generation rechargeable Li-ion batteries. [ABSTRACT FROM AUTHOR]

Binary metal oxides has been regarded as a promising class of electrode materials for high-performance energy storage devices since it offers higher electrochemical activity and higher capacity than mono-metal oxide. Besides, rational design of electrode architectures is an effective solution to further enhance electrochemical performance of energy storage devices. Here, the advanced electrode architectures consisting of carbon textiles uniformally covered by mesoporous NiCo2O4 nanowire arrays (NWAs) are successfully fabricated by a simple surfactant-assisted hydrothermal method combined with a short post annealing treatment, which can be directly applied as self-supported electrodes for energy storage devices, such as Li-ion batteries, supercapacitors. The as-prepared mesoporous NiCo2O4 nanowires consist of numerous highly crystalline nanoparticles, leaving a large number of mesopores to alleviate the volume change during the charge/discharge process. Electrode architectures presented here promise fast electron transport by direct connection to the growth substrate and facile ion diffusion path provided by both the abundant mesoporous structure in nanowires and large open spaces between neighboring nanowires, which ensures every nanowire participates in the ultrafast electrochemical reaction. Benefiting from the intrinsic materials and architectures features, the unique binder-free NiCo2O4/carbon textiles exhibit high specific capacity/capacitance, excellent rate capability, and cycling stability. [ABSTRACT FROM AUTHOR]

Flexible porous films are prepared from electrospun carbon nanofibers (CNFs) embedded with Co3O4 hollow nanoparticles (NPs) and are directly applied as self-supported electrodes for high-performance electrochemical capacitors. Uniform Co3O4 hollow NPs are well dispersed and/or embedded into each CNF with desirable electrical conductivity. These Co3O4-CNFs intercross each other and form 3D hierarchical porous hybrid films. Benefiting from intriguing structural features, the unique binder-free Co3O4 hollow NPs/CNF hybrid film electrodes exhibit high specific capacitance (SC), excellent rate capability and cycling stability. As an example, the flexible hybrid film with loading of 35.9 wt% Co3O4 delivers a SC of 556 F g−1 at a current density of 1 A g−1, and 403 F g−1 even at a very high current density of 12 A g−1. Remarkably, almost no decay in SC is found after continuous charge/discharge cycling for 2000 cycles at 4 A g−1. This exceptional electrochemical performance makes such novel self-supported Co3O4-CNFs hybrid films attractive for high-performance electrochemical capacitors. [ABSTRACT FROM AUTHOR]

Potassium‐ion hybrid capacitors (PIHCs) are regarded as one of the promising candidates for large‐scale energy storage technologies. Nevertheless, the lack of suitable anode materials combined with fast ion diffusion kinetics and favorable cycle stability restricts their application. Herein, a catalyst‐confined graphitization strategy is proposed to synthesize low‐cost coal‐based carbon anodes, which have controllable heteroatom co‐doping and rich defect sites, together with local graphitic domains. Density functional theory calculations and kinetic analysis are performed to uncover the coupling effect for heteroatom dual‐doping and defective structures. Importantly, the introduction of graphitic domains ensures good electric conductivity and charge transfer kinetics while preserving rich defects and active sites. The optimized NC‐950 exhibits superior potassium storage capacity, which delivers a high reversible specific capacity (363.3 mAh g−1), impressive rate capability (93.9 mAh g−1 at 2 A g−1), and stable cycling performance. As a practical device application, the PIHCs (NC‐950//AC) are assembled using the NC‐950 anode and commercial activated carbon (AC) cathode, which exhibits the maximum energy density of 97.0 Wh kg−1 and excellent cycling stability (10 000 cycles). Significantly, this work unveils a new pathway to developing low‐cost and fast reaction kinetics carbon anode for advanced electrochemical supercapacitors. [ABSTRACT FROM AUTHOR]