Search

Potassium‐ion batteries hold practical potential for large‐scale energy storage owing to their appealing cell voltage and cost‐effective features. The development of anode materials with high rate capability and satisfactory cycle lifespan, however, is one of the key elements for exploiting this electrochemical energy storage system at practical levels. Here, a template‐assisted strategy is reported for acquiring a bimetallic telluride heterostructure which is supported on N‐doped carbon shell (ZnTe/CoTe2@NC) that promotes diffusion of K+ ions for rapid charge transfer. It is shown that in telluride heterojunctions, electron‐rich Te sites and built‐in electric fields contributed by electron transfer from ZnTe to CoTe2 concomitantly provide abundant cation adsorption sites and facilitate interfacial electron transport during potassiation/depotassiation. The relatively fine ZnTe/CoTe2 nanoparticles imparted by the heterojunction result in high structural stability, together with a highly reversible capacity up to 5000 cycles at 5 A g−1. Moreover, using judiciously combined experiment and theoretical computation, it is demonstrated that the energy barrier for K+ diffusion in telluride heterojunctions is significantly lower than that in individual counterparts. This quantitative design for fast and durable charge transfer in telluride heterostructures can be of immediate benefit for the rational design of batteries for low‐cost energy storage and conversion. [ABSTRACT FROM AUTHOR]

Background: As the population ages, cognitive impairment and dementia have become one of the greatest health threats in older adults. Prior studies suggest that exergaming could improve cognitive function in older adults. To date, few long-term exergames intervention studies on older adults during the COVID-19 epidemic exist. This study aimed to investigate the effects of exergame on cognitive function in Chinese older adults, and to examine whether exergame was more effective than aerobic dancing for executive function and working memory. Methods: 55 participants (mean age = 65.4 ± 3.7 years) were randomly assigned to an exergame training (ET) group, an aerobic dancing training (ADT) group, or a control (CON) group. The ET and ADT groups received 36 sessions (three 75-min training sessions per week, exercise intensity = 65 to 75% HRmax) during a 12-week period. The outcome measures for cognitive function included working memory measured by the N-back test, and executive function measured by the Stroop test. Results: The ET group showed a significantly positive effect in working memory, relative to the ADT (accuracy in 1-back test: ES = 0.76, p < 0.01), and CON group (accuracy in 1-back test: ES = 0.87, p = 0.02). Moreover, the performance in the Stroop test showed some improvements in executive function after intervention in the ET and ADT groups (Stroop intervention effect: ES = 0.38; p = 0.25). Conclusions: Exergame had a positive benefit in improving cognitive functions in older adults without cognitive impairment. Long-term exergame training could improve working memory in older adults. Exergame and aerobic dancing can efficiently improve inhibitory control of executive function in older adults. Maintaining an active lifestyle is protective of cognitive health in older adults. [ABSTRACT FROM AUTHOR]

Pt‐based nanomaterials are now the most reliable catalysts for oxygen reduction reaction (ORR). However, the low atomic utilization efficiency and poor stability severely limit their widespread application. Herein, a facile molten salt approach for synthesizing N‐doped porous carbon embedded with Pt3Fe intermetallic nanoparticles is presented. The Pt loading of the as‐prepared materials is as low at 5.91 wt. %, while exhibiting a half‐wave potential of 0.85 V and diffusion limiting current density of −5.68 mA cm−2 in alkaline condition, which is superior to commercial Pt/C (0.83 V, −5.48 mA cm−2). As cathode for Zn‐air battery, the power density and specific capacity up to 130.0 mW cm−2 and 833 mAh g−1, respectively, are outperforming Pt/C batteries (85.8 mW cm−2, 632 mAh g−1). The theoretical calculations identify the origin of activity on Pt3Fe; the Pt3Fe (111) plane exhibits more positive activity than (200) plane. [ABSTRACT FROM AUTHOR]

Hierarchical hybrid heteroarchitectures possess attractive structural/compositional merits for lithium‐ion batteries (LIBs). Herein, a facile yet in situ growth strategy is proposed to scalably synthesize hierarchical porous ZnO/ZnFe2O4 hybrid nanofibers (NFs) with robust core/shell heterostructure toward LIBs. In such hybrids, 2D ZnFe2O4 nanosheets (NSs) are uniformly decorated on single‐crystalline ZnO core NFs, thereby affording more exposed active sites, a fast ion diffusion kinetic, and structural stability of electrodes during repeated cycling. As a result, benefiting from the unique hierarchical porous core/shell architecture and synergistic effects between the stable substrate of ZnO NFs and high‐capacity promoter of ZnFe2O4 NSs, the optimized ZnO/ZnFe2O4 hybrid as an anode for LIBs delivers a large reversible capacity of ≈688 mAh g−1 at 0.1 A g−1, high rate capability (≈288 mAh g−1 at 2.0 A g−1), and remarkable cyclability (≈491 mAh g−1 even over 250 cycles at 0.5 A g−1) for efficient lithium storage. This work highlights the rational design of a hierarchical architecture with a stable substrate and high‐capacity phases for next‐generation energy storage applications. [ABSTRACT FROM AUTHOR]

Among the various semiconductor materials, zinc telluride possesses the lowest electron affinity and ultrafast charge separation capability, facilitating improved charge transfer kinetics. In addition, ZnTe has a relatively high density, contributing to high volumetric capacity. Here, 1D N‐doped carbon‐coated ZnTe core‐shell nanowires (ZnTe@C) are designed and prepared via a facile ion‐exchange and carbonization technique. When evaluated as anode for metal ion batteries, it demonstrates superior electrochemical performance in both Li and Na ion storage, including high gravimetric and volumetric capacities (1119 mA h g−1 and 906 mA h cm−3, respectively, at 100 mA g−1 for Li ion storage), excellent high‐rate capability, and long‐term cycling stability. This remarkable electrochemical performance is attributed to the low electron affinity and high density of ZnTe, and the amorphous nature of the N‐doped carbon layer in the heterostructured ZnTe@C nanowires, which not only provide fast charge transfer paths, but also effectively maintain the structural and electrical integrity of the ZnTe. The strategy of embedding high density and high‐performance active materials in highly conductive nanostructures represents an effective way of achieving electrode materials with excellent gravimetric and volumetric capacities towards superior energy storage systems. [ABSTRACT FROM AUTHOR]

A group of newly reported antiperovskite nitrides CuxIn1−xNNi3 (0≤x≤1) with tunable composition are employed as electrocatalysts for the hydrogen evolution reaction (HER). Cu0.4In0.6NNi3 shows the highest intrinsic performance among all developed catalysts with an overpotential of merely 42 mV at 10 mA cmgeo−2. Stability tests at a high current density of 100 mA cmgeo−2 show its super‐stable performance with only 7 mV increase in overpotential after more than 60 hours of measurement, surpassing commercial Pt/C (increase of 170 mV). By partial substitution, the derived antiperovskite nitride achieves a smaller kinetic barrier of water dissociation compared to the unsubstituted InNNi3 and CuNNi3, revealed by first‐principle calculations. It is found that the partially substituted CuxIn1−xNNi3 possesses a thermal neutral and desirable Gibbs free energy of hydrogen for HER, ascribed to the tailoring of the energy of d‐band center arose by the A‐site (A=Cu or In) substitution and a resulting optimization of adsorbate interactions. [ABSTRACT FROM AUTHOR]

The cost‐efficient ZnMnO3 has attracted increasing attention as a prospective anode candidate for advanced lithium‐ion batteries (LIBs) owing to its resourceful abundance, large lithium storage capacity and low operating voltage. However, its practical application is still seriously limited by the modest cycling and rate performances. Herein, a facile design to scalable synthesize unique one‐dimensional (1D) mesoporous ZnMnO3 nanorods (ZMO‐NRs) composed of nanoscale particles (≈11 nm) is reported. The 1D mesoporous structure and nanoscale building blocks of the ZMO‐NRs effectively promote the transport of ions/electrons, accommodate severe volume changes, and expose more active sites for lithium storage. Benefiting from these appealing structural merits, the obtained ZMO‐NRs anode exhibits excellent rate behavior (≈454 mAh g−1 at 2 A g−1) and ultra‐long term cyclic performance (≈949.7 mAh g−1 even over 500 cycles at 0.5 A g−1) for efficient lithium storage. Additionally, the LiNi0.8Co0.1Mn0.1O2//ZMO‐NRs full cell presents a practical energy density (≈192.2 Wh kg−1) and impressive cyclability with approximately 91 % capacity retention over 110 cycles. This highlights that the ZMO‐NRs product is a highly promising high‐rate and stable electrode candidate towards advanced LIBs in electronic devices and sustainable energy storage applications. [ABSTRACT FROM AUTHOR]

With the increasing energy demand of electronic devices and electric vehicles, the achievement of anode materials for lithium-ion batteries with high specific capacity and superior rate capability and cycling stability still remains a challenge. Herein, we report a novel strategy to prepare the core–shell mesoporous single-crystalline MnOx nanofibers@graphene (PSCMnOx@G) through a “spraying–rapid freezing” process. The elastic graphene shell not only improves the conductivity of the electrode but can also substantially inhibit the collapse of MnOx nanofibers (NFs) over continuous discharge–charge cycles. Moreover, the double-exchange interaction of manganese mixed-valence ions further improves the conductivity of manganese oxide, and Li ion diffusion is significantly enhanced by the vertically aligned single-crystalline and mesoporous structure of MnOx NFs. As a result, the PSCMnOx@G exhibits an ultrahigh rate performance (1072 mA h g−1 at 0.1 A g−1 and 419 mA h g−1 at 10 A g−1), which is among the best ever reported for MnOx based anodes, as well as excellent cycling stability (1162 mA h g−1 at 2 A g−1 over 500 cycles). [ABSTRACT FROM AUTHOR]