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Long-term stable secondary batteries are highly required. Here, we report a unique microcapsule encapsulated with metal organic frameworks (MOFs)-derived Co3O4 nanocages for a Li-S battery, which displays good lithium-storage properties. ZIF-67 dodecahedra are prepared at room temperature then converted to porous Co3O4 nanocages, which are infilled into microcapsules through a microfluidic technique. After loading sulfur, the Co3O4/S-infilled microcapsules are obtained, which display a specific capacity of 935 mAh g−1 after 200 cycles at 0.5C in Li-S batteries. A Coulombic efficiency of about 100% is achieved. The constructed Li-S battery possesses a high rate-performance during three rounds of cycling. Moreover, stable performance is verified under both high and low temperatures of 50 °C and −10 °C. Density functional theory calculations show that the Co3O4 dodecahedra display large binding energies with polysulfides, which are able to suppress shuttle effect of polysulfides and enable a stable electrochemical performance. [ABSTRACT FROM AUTHOR]

Among many types of batteries, Li-ion and Li-S batteries have been of great interest because of their high energy density, low self-discharge, and non-memory effect, among other aspects. Emerging applications require batteries with higher performance factors, such as capacity and cycling life, which have motivated many research efforts on constructing high-performance anode and cathode materials. Herein, recent research about cathode materials are particularly focused on. Low electron and ion conductivities and poor electrode stability remain great challenges. Three-dimensional (3D) porous nanostructures commonly exhibit unique properties, such as good Li+ ion diffusion, short electron transfer pathway, robust mechanical strength, and sufficient space for volume change accommodation during charge/discharge, which make them promising for high-performance cathodes in batteries. A comprehensive summary about some cutting-edge investigations of Li-ion and Li-S battery cathodes is presented. As demonstrative examples, LiCoO2, LiMn2O4, LiFePO4, V2O5, and LiNi1−x−yCoxMnyO2 in pristine and modified forms with a 3D porous structure for Li-ion batteries are introduced, with a particular focus on their preparation methods. Additionally, S loaded on 3D scaffolds for Li-S batteries is discussed. In addition, the main challenges and potential directions for next generation cathodes have been indicated, which would be beneficial to researchers and engineers developing high-performance electrodes for advanced secondary batteries. [ABSTRACT FROM AUTHOR]

High energy-storage Li-ion battery needs a high-capacity anode. However, current graphite-based anode doesn't meet this requirement, thus developing high performance anode materials is highly needed and significant. Here, we provide a rational engineering of a multi-layered hollow structure combining with surface coating of polyamine (PANI) layer, forming a Co 3 O 4 /NiO@PANI hybrid using for Li-ion battery anode. PANI is able to effectively improve the conductivity of active materials; besides, PANI is flexible, which can prevent the collapse of the structure caused by volume-expansion during charge and discharge. The multi-layered morphology improves the utilization ratio of voids inside the conventional hollow structured materials, which is significant to improve capacity in practical applications. The Co 3 O 4 /NiO@PANI hybrid-based anode shows a capacity of 1049 mAh g−1 along with a Coulombic efficiency of 99.3% after 100 cycles of 0.2 A g−1. Rate-performance of Co 3 O 4 /NiO@PANI exceeds that of the bare Co 3 O 4 /NiO. It is believed that the hierarchical structure combining multi-layered hollow morphology with surface coating of conductive polymer presented here would find broad applications for developing high-performance energy-storage hybrids. [Display omitted] • A novel Co 3 O 4 /NiO@polyamine is developed for Li-ion battery anode. • Polyamine nanorods on Co 3 O 4 /NiO keep robust during cycling. • Co 3 O 4 /NiO@polyamine anode exhibits a high and stable capacity. • A recoverable rate-performance of Co 3 O 4 /NiO@polyamine is achieved. [ABSTRACT FROM AUTHOR]

Cathode materials of Li-ion batteries are important for their overall Li-storage performance. However, current cathodes are still non-ideal with rapid capacity decay and poor stability. Herein, a composite cathode consisting of ternary LiMn 1/3 Co 1/3 Ni 1/3 O 2 particles anchored on reduced graphene oxide sheets is presented, which is prepared through a simple route. The composite cathode exhibits a stable capacity exceeding 120 mAh g−1 after 500 cycles at 0.2 C, along with a high Coulombic efficiency close to 100%, which are obviously improved compared to the pure LiMn 1/3 Co 1/3 Ni 1/3 O 2. In addition, the rate-performance of the composite is also significantly enhanced. We believe that the good electrochemical performance and the general preparation approach are able to enable the composite to find significant applications in high-performance secondary batteries. [ABSTRACT FROM AUTHOR]

Nano-engineering graphene-based composite anodes have motivated broad investigations of the high energy density lithium-ion batteries. Here, a sandwich-like and porous NiCo 2 O 4 @reduced graphene oxide (rGO) nanocomposite was presented. Through an incipient dipping process, the NiCo 2 O 4 precursors attach on the rGO densely, which significantly improves the material loading of the NiCo 2 O 4 @rGO composites. Serving as an anode of the lithium-ion battery, the NiCo 2 O 4 @rGO composites exhibit an unprecedented capacity of 1566 mAh g −1 cycling at a current density of 1000 mA g −1 over 700 times; while a capacity of 886 mAh g −1 at 100 mA g −1 over 100 cycles was achieved upon a NiCo 2 O 4 @rGO//LiCoO 2 full-cell, which indicates a promising potential for high energy density battery applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Ga-Sn liquid alloy-encapsulated microcapsule is developed as self-healing Li-ion battery anode. • The liquid alloy microcapsules are prepared by using an oil-in-water emulsion. • Liquid alloy-encapsulated microcapsules exhibit high capacity and rate-performance. • Promising applications of Ga-Sn liquid alloy-encapsulated microcapsules is achievable. Engineering emerging anodes for lithium-ion batteries is of great significance. Here, we develop a self-healing anode composing of Ga-Sn liquid alloy infilling in a microcapsule. The microcapsules are prepared by using an oil-in-water emulsion. Liquid state of the Ga-Sn alloy in microcapsules is able to reduce structural failure on the basis of a self-healing mechanism during long-term cycling; the voids of microcapsules alleviate volumetric change of Ga-Sn alloy upon charge–discharge; and carbon shell improves the conductivity. The liquid alloy-encapsulated microcapsule anode exhibits a capacity of 711.6 mA h g−1 after 500 cycles and an ultrahigh Coulombic efficiency of 99.9 %. Moreover, the microcapsules present a recoverable rate-performance. Those properties enable the self-healing Ga-Sn liquid alloy-encapsulated microcapsules developed here to have a good potential for practical applications. [ABSTRACT FROM AUTHOR]

• A binder-free composite cathode is developed for Li-S batteries. • Stable capacity and recoverable rate-performance are achieved. • Density functional theory calculations show the composite has large binding energies with polysulfides. • Three-dimensional composite facilitates ion diffusion and electron transport. [Display omitted] A binder-free porous graphene like-C 3 N 4 nanoflakes/carbon cloth/sulfur lithium-sulfur battery cathode prepared through a thermal polymerization method is presented. On the basis of the density functional theory calculations on the bonds between g-C 3 N 4 and lithium polysulfides including Li 2 S 4 , Li 2 S 6 and Li 2 S 8 , it is found the cathode possesses robust binding energies towards polysulfides and an improved conductivity, which would enable a strong suppression for the transfer of the lithium polysulfides. The prepared porous binder-free cathode exhibits a high capacity of 892 mAh g−1 after cycling 250 times at 0.2 C and a well-recoverable rate-performance, which indicates a good potential to construct high-performance lithium-sulfur batteries for practical applications. [ABSTRACT FROM AUTHOR]

Hierarchical materials have been considered promising for secondary battery electrodes owing to their capability of accommodating volumetric change of active materials and providing short pathways for rapid transportation of ions and electrons. Herein, we present a rod-on-tube composite consisting of cobalt molybdate (CoMoO 4) nanotubes coating with polyaniline (PANI) hydrogel nanorods, which exhibits a high electrochemical performance as Li-ion battery anode. The hierarchical CoMoO 4 @PANI is prepared through in-situ polymerizing PANI nanorods on the CoMoO 4 nanotubes. The rod-on-tube structure could alleviate the volumetric change of CoMoO 4 during lithiation-delithiation, and improve conductivity for electron transfer. When cycling at 0.5 A g-1, the presented CoMoO 4 @PANI anodes exhibit a large capacity of 805 mAh g-1 after 150 cycles along with a Coulombic efficiency of 99%, which are both exceeding those of the pristine CoMoO 4. A well-recoverable rate-performance is achieved. Furthermore, the density of state (DOS) and band gap of the CoMoO 4 @PANI and pristine CoMoO 4 are also investigated by using density functional theory (DFT) calculations. Image 1 • A rod-on-tube CoMoO 4 @hydrogel composite anode is presented. • Rod-on-tube structure enables rapid transportation of ions and electrons. • CoMoO 4 @hydrogel composite exhibits a high electrochemical performance. • Density function theory calculations verify an improved conductivity. [ABSTRACT FROM AUTHOR]