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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]

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]

By means of zincophilic regulation and protection of covalent organic framework (COF), uniform Zn ion deposition can be induced to inhibit dendrite growth and prevent chemical corrosion reactions. Moreover, abundant zincophilic sites and excellent zinc ion conduction pathway in the interfacial layer of COF can optimize the zinc ion transfer kinetics between electrolyte and Zn anode, thus inducing uniform Zn ion migration, nucleation, dissolution/plating. To realize the efficient and stable utilization of zinc anode. [Display omitted] Zn-ion energy storage devices will play important roles in the future energy storage field. However, Zn-ion device development suffers significantly from adverse chemical reactions (dendrite formation, corrosion, and deformation) on the Zn anode surface. Zn dendrite formation, hydrogen evolution corrosion, and deformation combine to degrade Zn-ion devices. Zincophile modulation and protection using covalent organic frameworks (COF) inhibited dendritic growth by induced uniform Zn ion deposition, which also prevented chemical corrosion. The Zn@COF anode circulated stably for more than 1800 cycles even at high current density in symmetric cells and maintained a low and stable voltage hysteresis. This work explains the surface state of the Zn anode and provides information for further research. [ABSTRACT FROM AUTHOR]

Abstract The rechargeable lithium sulfur batteries are investigated as a promising energy storage system. Various materials as the host of sulfur have been applied to improve the performance of lithium sulfur batteries. However, the poor conductivity of sulfur and polysulfides shuttle effect result in poor cycling performance and lower specific capacity. Here, a novel chemical and physical entrapment strategy to improve the electrochemical performance is introduced by designing and synthesizing a 3D network composite which consists of intertwined TiO 2 -B nanotubes and carbon nanotubes as the sulfur hosts. In this unique structure, carbon nanotubes serve as the long-range conductive network which facilitates the transfer of electrons during redox reaction. Theoretical calculations reveal that TiO 2 -B provides a strong chemical binding for polysulfides, and each TiO 2 -B nanotube as an independent reaction chamber provides an efficient barrier to restrict the shuttling of the polysulfides. Specifically, the electrodes exhibit an ultralow capacity fading of 0.05% per cycle over 800 discharge/charge cycles, and a high specific capacity of 580 mAh g−1 at 1C rate after 300 cycles even with high areal sulfur loading of 3.2 mg cm−2. Graphical abstract Image 1 Highlights • TiO 2 -B nanotubes as the host of sulfur exhibits excellent performance. • The cathodes with high areal sulfur loading was prepared. • The stirring condition significantly lengthens the TiO 2 -B nanotubes. • Carbon nanotubes serve as the conductive substrate for the network composite. [ABSTRACT FROM AUTHOR]

Aqueous zinc-based energy storage system plays an increasingly important role in the energy storage field because of the low cost, high safety, and high capacity. At present, zinc-based cells developed use excessive zinc, which increases volume and mass and sacrifices some energy density. The anode-free construction is realized by effective interface modification layer to address these issues. Nitrogen doped porous carbon nanocages modulation layer facilitates the uniform distribution of electric field, promote the uniform transport of zinc ions, further optimize nucleation and inhibit dendrite growth. This strategy can realize the homogeneous zinc nucleation and growth to obtain efficient and stable zinc plating/stripping. The Cu/NPCNs electrodes keep stable Zn plating/stripping of 100 cycles at large current density of 5 mA cm−2 and still maintain high CE (99%). Based on this anode-free foundation, an anode-free Zn ion capacitor exhibits high specific capacity of 106 mAh g-1 at 1 mA cm−2 and maintains high-capacity stability of 98% after 2000 cycles at 1 mA cm−2. The energy density of 101 Wh kg−1 is higher than that of the zinc-metal anode system. This anode-free design strategy promotes the further development of zinc-based energy storage systems with high energy density. • A new type of anode-free Zn ion hybrid capacitor is constructed. • The interface strategy optimize Zn ion nucleation and inhibit Zn dendrite growth. • Theoretical calculations prove that NPCNs optimize transport kinetics of Zn ions. • The anode-free Zn ion hybrid capacitor exhibit increased energy density. • The anode-free Zn ion hybrid capacitor have excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

• A novel hydrogen ion supercapattery was assembled. • N and P co-doped carbon paper was effectively acted as the cathode substrate. • The cyclic stability could be improved by modifying the cathode with Nafion. Hydrogen ion battery is a promising energy storage device due to its advantages of non-pollution, excellent rate capability and feasibility at low temperature. Herein, we assemble a novel rechargeable hydrogen ion supercapattery with the iodine-absorbed carbon paper doped with N and P (I 2 -NP-CP) as the cathode electrode and molybdenum trioxide as the anode electrode. Typically, the I 2 -NP-CP electrode shows the superior rate capability from 1 A g−1 (174.7 mAh g−1, 483.8 F g−1) to 20 A g−1 (111.1 mAh g−1, 307.7 F g−1), mainly ascribed to the strong interaction between iodine and the NP-CP substrate. Furthermore, electrochemical measurement of the I 2 -NP-CP@Nafion//MoO 3 supercapattery manifests that the electrodes exhibit excellent cycling stability, retaining 124.3 mAh g−1 after 500 cycles at 15 A g−1, accounting for 93.2 % of the initial capacity. Although some IO 3 − dissolves in the electrolyte due to the weak chemical interaction between IO 3 − and NP-CP, and cannot be completely reduced to I− during discharge process, it can be improved by modification of electrode with Nafion resin to further better the cycling stability. The excellent electrochemical properties in this study show the possibility for the development of novel rechargeable hydrogen ion supercapattery system. [Display omitted] [ABSTRACT FROM AUTHOR]

• 3D-printed g-C 3 N 4 interphase realizes dendrite-free growth and anticorrosion. • The DFT proves lower energy barrier to further induces uniform of Zn distribution. • The simulation suggests that g-C 3 N 4 can effectively facilitate electric distribution. • The Zn/C 3 N 4 //AC supercapacitor and Zn/C 3 N 4 //MnO 2 battery show excellent stability. Further commercial deployment of Zn anode has been severely restricted by the notorious tip-induced dendrite growth. The solutions establishing effective zincophile interphase have been proposed to conquer this difficulty. Yet, how to effectively construct zinc deposition interphase is challenging. Herein, we construct a zincophile interphase based on 3D-printed g-C 3 N 4 modulating interface to concurrently achieve homogeneous zinc nucleation and a dendrite-free growth. The Zn/C 3 N 4 anode affords lower the energy barrier and more homogeneously charge distribution to facilitate highly reversible Zn plating/stripping. The symmetric Zn/C 3 N 4 cell presents appreciably low voltage hysteresis and superior cycling stability compared to the bare Zn. Furthermore, the Zn/C 3 N 4 //AC supercapacitor and Zn/C 3 N 4 //MnO 2 battery show long cycle stability. The novel strategy of 3D-printed modulating coatings is straightforward and scalable and provides the design concept to the realization of the long-life aqueous zinc metal batteries. [ABSTRACT FROM AUTHOR]

A novel Sr-doped P-Na 0.57 Sr 0.05 Mn 0.6 Ni 0.2 Co 0.2 O 2 consisting of multiple-layer oriented stacking nanoflakes with Na+/vacancies is constructed via a sol-gel method. • A P2 type compound consisting of multiple-layer oriented stacking nanoflakes was synthesized. • Sr2+ is embedded in the sodium ion layer to increases the spacing of crystal layers. • Na 0.57 Sr 0.05 Mn 0.6 Ni 0.2 Co 0.2 O 2 cathode exhibits excellent cyclic and rate performance. • It exhibits low transport energy barrier due to Na+/vacancies and wide ionic channels. Sodium ion batteries (SIBs) are an attractive option for energy storage because of their low cost and extensive Na resources. A novel Sr-doped P-type Na 0.57 Sr 0.05 Mn 0.6 Ni 0.2 Co 0.2 O 2 (NSMNC) consisting of multiple-layer oriented stacking nanoflakes is constructed via a sol-gel method. It is the first time that high-valence metal ions with large radius are introduced into the sodium ionic layer to optimize its structure. The substitution of bivalent strontium for monovalent sodium leads to the formation of equivalent Na+/vacancies. Meanwhile, the intercalation of strontium enlarges the cell parameters, providing wide channels for ionic transport. The electrode exhibits a reversible capacity of 120.9 mAh g−1 at 0.1C with retention up to 85.6% after 200 cycles. Besides, it still keeps a capacity of 101.1 mAh g−1 at 1C with high retention of 81.5% after 200 cycles. Owing to the Na+/vacancies and wide ionic channels, NSMNC shows excellent ionic diffusion ability and low transport energy barrier. This work offers a feasible strategy for the development of promising layered oxide cathode materials for SIBs. [ABSTRACT FROM AUTHOR]