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Aqueous Zn–MnO2 batteries have great potential as flexible energy storage devices owing to their low cost, high energy density, safety, and environmental friendliness. However, their development is plagued by the poor cycling stability, and the use of heavy zinc foil as the anode is antithetical to the flexible devices. Herein, we construct a high-performance and stable flexible rechargeable quasi-solid-state Zn–MnO2 battery using MnO2 nanorod arrays and tiny Zn nanoparticles uniformly deposited on N-doped porous carbon cloth as the free-standing cathode and anode, respectively. The 3D porous nitrogen-doped carbon cloth substrate with high electric conductivity and good flexibility serves as an ideal support for guest active materials of MnO2 nanorod arrays and tiny Zn nanoparticles, which can effectively buffer the volume change giving rise to good cycling ability. Significantly, the device is able to deliver a remarkable capacity of 353 mA h g−1 and good cycling stability (93.6% after 1000 cycles) in an aqueous electrolyte. Moreover, when using PVA/ZnCl2/MnSO4 gel as the electrolyte, the as-fabricated quasi-solid-state Zn–MnO2 battery still achieves a high energy density of 440 W h kg−1, high power density of 7.9 kW kg−1 and excellent cycling ability. This work heralds new opportunities in the development of high-performance, low-cost, safe and flexible electronic devices. [ABSTRACT FROM AUTHOR]

Flexible lithium-ion batteries (LIBs) have recently attracted increasing attention with the fast development of bendable electronic systems. Herein, a facile and templatefree solvothermal method is presented for the fabrication of hybrid yolk-shell CoS2 and nitrogen-doped graphene (NG) sheets. The yolk-shell architecture of CoS2 encapsulated with NG coating is designed for the dual protection of CoS2 to address the structural and interfacial stability concerns facing the CoS2 anode. The as-prepared composite can be assembled into a film, which can be used as a binder-free and flexible electrode for LIBs that does not require any carbon black conducting additives or current collectors. When evaluating lithium-storage properties, such a flexible electrode exhibits a high specific capacity of 992 mAh g-1 in the first reversible discharge capacity at a current rate of 100 mA g-1 and high reversible capacity of 882 mAh g-1 after 150 cycles with excellent capacity retention of 89.91 %. Furthermore, a reversible capacity as high as 655 mAh g-1 is still achieved after 50 cycles even at a high rate of 5 C due to the yolk-shell structure and NG coating, which not only provide short Li-ion and electron pathways, but also accommodate large volume variation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hollow MoS2 MACCs have been successfully synthesized. [•] Initial discharge capacity of 1545mAhg−1 is obtained at 100mAg−1. [•] Hollow MoS2 MACCs show enhanced cycling stability and rate capability. [•] Amorphous carbon can improve electrochemical performance. [ABSTRACT FROM AUTHOR]

A novel surface phosphate strategy was adopted to dramatically improve the charge transport, ion diffusion, electroactive sites, and cycle stability of mesoporous NiCo 2 O 4 nanowire arrays (NWAs), drastically boosting their electrochemical properties. Consequently, the as-prepared phosphated NiCo 2 O 4 NWA (P-NiCo 2 O 4 NWA) electrode achieved excellent energy storage performance as a bifunctional anode material for both lithium ion batteries (LIBs) and sodium ion batteries (SIBs). When evaluated as an anode for LIBs, this P-NiCo 2 O 4 NWA electrode showed a high reversible capacity up to 1156 mA h g -1 for 1500 cycles at 200 mA g -1 without appreciable capacity attenuation, while in SIBs, the electrode could also deliver an admirable initial capacity as high as 687 mA h g -1 and maintained 83.5% of this after 500 cycles at the same current density. Most important, when the current density increased from 100 to 1000 mA g -1 , the capacity retention was about 63% in LIBs and 54% in SIBs. This work may shed light on the engineering of efficient electrodes for multifunctional flexible energy storage device applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Flexible lithium-ion batteries (LIBs) have recently attracted increasing attention with the fast development of bendable electronic systems. Herein, a facile and template-free solvothermal method is presented for the fabrication of hybrid yolk-shell CoS2 and nitrogen-doped graphene (NG) sheets. The yolk-shell architecture of CoS2 encapsulated with NG coating is designed for the dual protection of CoS2 to address the structural and interfacial stability concerns facing the CoS2 anode. The as-prepared composite can be assembled into a film, which can be used as a binder-free and flexible electrode for LIBs that does not require any carbon black conducting additives or current collectors. When evaluating lithium-storage properties, such a flexible electrode exhibits a high specific capacity of 992 mAh g(-1) in the first reversible discharge capacity at a current rate of 100 mA g(-1) and high reversible capacity of 882 mAh g(-1) after 150 cycles with excellent capacity retention of 89.91%. Furthermore, a reversible capacity as high as 655 mAh g(-1) is still achieved after 50 cycles even at a high rate of 5 C due to the yolk-shell structure and NG coating, which not only provide short Li-ion and electron pathways, but also accommodate large volume variation., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)