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The practical capacity of conversion-type Cu-based materials is low and the structural instability usually results in poor capacity retention and rate performance. Carbon quantum dots (CDs) composites are an effective way to overcome the above-mentioned shortcomings. Herein, a core–shell architecture self-assembled by CDs and Cu2O was well engineered. Such a unique construction efficiently integrates the advantages of CDs and the functional cladding interface. The constrain effect of the CDs shell effectively limits the collapse of the structure and the dissolution of active substances in Cu2O, and improves the phase transformation reaction and reaction kinetics of the composite. Theoretical calculations show that CDs reduce the ion diffusion energy barrier and improve the electrical conductivity of Cu2O. In particular, the optimized Cu2O-CDs-20 provides a high capacity of 425 mA h g−1 at 0.1 A g−1 (only 260 mA h g−1 for pure Cu2O) as the cathode for aqueous zinc ion batteries (AZIBs) and shows superior cycling stability and rate performance. The excellent performance of the composite should be contributed to the CDs modification and the conversion-type zinc storage mechanism of Cu2O as confirmed by in situ XRD, in situ Raman spectroscopy and electrochemical characterizations. [ABSTRACT FROM AUTHOR]

The high Zn ion desolvation energy, sluggish Zn deposition kinetics, and top Zn plating pattern are the key challenges toward practical Zn anodes. Herein, these key issues are addressed by introducing zinc pyrovanadate (ZVO) as a solid zinc‐ion conductor interface to induce smooth and fast Zn deposition underneath the layer. Electrochemical studies, computational analysis, and in situ observations reveal the boosted desolvation and deposition kinetics, and uniformity by ZVO interface. In addition, the anti‐corrosion ability of Zn anodes is improved, resulting in high Zn stripping/plating reversibility. Consequently, the ZVO layer renders fast rechargeability and durable life in both Zn symmetric cells (1050 h at 10 mA cm−2, 1 mAh cm−2) and Zn/V2O5 batteries (79.1% capacity retention after 1000 cycles at 2 A g−1) with low electrode polarization. This work provides insights into the design of solid zinc‐ion conductor interface to enhance the interface stability and kinetics of Zn metal anodes. [ABSTRACT FROM AUTHOR]

The carbon‐coated LiFe0.5Mn0.5PO4 (C/LFMP) and carbon‐coated LiFe0.5Mn0.5PO4@Li2SiO3 (C/LFMP‐LSO) could be successfully prepared by high temperature solid‐state reaction. Even though the crystal structure and morphology of C/LiFe0.5Mn0.5PO4 was not changed by Li2SiO3 coating, Li2SiO3 modification was able to facilitate the diffusion of lithium ions, resulting in an excellent rate performance and cyclic stability of C/LFMP‐1LSO (1 wt %). The reversible discharge specific capacities of C/LFMP‐1LSO are 157.6 mAh g−1 and 106.3 mAh g−1 at 0.1C and 10C, respectively. Meanwhile, the C/LFMP‐1LSO was cycled for 500 times at 5C with a capacity retention rate of 85.3 %. Furthermore, at a low temperature of 6 °C and 0.2C, the C/LFMP‐1LSO displayed good low temperature performance with a discharge specific capacity of 140.6 mAh g−1. Li2SiO3 coating was considered an effective way to boost the overall electrochemical performance of C/LFMP. [ABSTRACT FROM AUTHOR]

Aqueous Zn-ion batteries (ZIBs) show great potential in energy storage systems because of their high theoretical capacities, high safety, low cost, and environmental friendliness. The lack of suitable cathode materials for sustaining the Zn2+ intercalation/deintercalation severely restricts their further application. Herein, calcium-intercalated birnessite MnO2 anchored on carbon nanotubes (CNTs) was designed as a cathode for ZIBs. The cathode material can be facilely produced by a simple one-pot reaction process. The external calcium-intercalated MnO2 with large layer spacing affords a fast ionic migration rate and the internal CNTs serving as a structural framework endow the electrode with better electrical conductivity. Benefiting from the larger interlayer spacing and the enhanced electrical conductivity, the CNT-CaMO cathode shows a high specific capacity of 351.8 mA h g−1 at 200 mA g−1 and a long cycle life over 6000 cycles. Besides, the H+ and Zn2+ co-intercalation storage mechanism was confirmed by ex situ XRD, SEM, and XPS analyses. This work opens up a new way to develop aqueous ZIB cathode materials with a high reversible capacity and long cycle life. [ABSTRACT FROM AUTHOR]

Currently, emerging battery technologies are being studied intensively. The lack of ideal electrode materials remains a key hindrance to further development of new batteries. The novel MXene material, due to its unique structural characteristics and physicochemical properties, shows the ability to enhance the electrochemical performance of the electrode. In addition to the adjustable layer spacing, because of excellent electrical conductivity, rich chemical composition, and controllable surface chemistry, MXene has the potential for use in diverse applications as an ideal electrode material in various battery systems. This review covers the recent progress achieved in research of the zinc‐ion energy storage of MXenes, including MXene‐based cathodes, MXene‐derived cathodes, MXene‐modified zinc anodes, and electrolyte additives. Moreover, further structural design and reaction mechanisms of MXenes in zinc‐ion storage are explored. [ABSTRACT FROM AUTHOR]

The yolk‐shell structure exhibits fascinating and important properties for energy storage devices. The carbon shell significantly improves the good electrical conductivity and the stable micro‐/nanostructures of the active material increases utilization. MnO2@C with a yolk‐shell structure shows high reversibility, good rate performance, and excellent cycling stability for aqueous Zn‐ion batteries. The Zn‐ion battery with MnO2@C could realize a high reversible capacity of 239 mAh g−1 at 0.1 A g−1. In particular, at a quite high current density of 2 A g−1, it achieves capacity of 91 mAh g−1. The Zn‐ion battery has excellent capacity retention of up to 1000 cycles at 1 A g−1. The yolk‐shell structure plays an important role in improving the battery performance. [ABSTRACT FROM AUTHOR]