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Copper selenide as an anode for lithium-ion batteries suffers from volume expansion/contraction, while constructing nanostructured copper selenide with other components is considered as an effective strategy. In this work, Cu2−xSe@C@Sb2Se3 nanosheets were fabricated through a two step solvothermal procedure with the assistance of glucose. Such a structure can facilitate the migration rate of Li+, enhance the electrical conductivity, buffer the volume variation and prohibit the aggregation of the electrode. As a result, Cu2−xSe@C@Sb2Se3 exhibits good electrochemical performance with a specific capacity of 341 mA h g−1 after 100 cycles at a current density of 100 mA g−1 and 153 mA h g−1 at a rate of 2000 mA g−1. Such a structural design and synthetic strategy may also be applied to explore other nanocomposites to improve the electrochemical performance. [ABSTRACT FROM AUTHOR]

The design and fabrication of the materials to improve their performance are crucial for energy storage of lithium-ion batteries and supercapacitors. Herein, the CuCo 2 S 4 nanocrystallites grown on N-doped amorphous carbon coated CNTs are synthesized via a facile solvothermal method (CNTs@NC@CuCo 2 S 4 ). The N-doped amorphous carbon layer with functional groups can effectively strengthen the adhesion between CNTs matrix and CuCo 2 S 4 nanocrystallites. The combination of nanocrystallites and the CNTs not only shortens the diffusion path of the electrolyte, but also enhances the electrical conductivity of the electrode. As a result, the CNTs@NC@CuCo 2 S 4 displays excellent electrochemical performance both in lithium-ion batteries and supercapacitors. The reversible capacity can be retained at 783 mAh g −1 after 100 cycles at the current density of 100 mA g −1 . And the discharge capacity of 507 mAh g −1 is still maintained after 60 cycles even at high rate of 5000 mA g −1 . As the electrode for supercapacitors, the CNTs@NC@CuCo 2 S 4 delivers good capacitive performance with high capability (1604 F g -1  at 1 A g −1 ), good rate capability, and enhanced cycling stability, with 93.6% capacitance retention after 2000 cycles at the current density of 2 A g −1 . [ABSTRACT FROM AUTHOR]

Transition metal sulfides as anodes for lithium-ion batteries (LIBs) have attracted much attention because of their large Li + storage capacity. However, the lower electrical conductivity and rapid capacity fading during the charge/discharge process strictly prohibit their practical applications. Here, a new strategy is adopted to accommodate the volume change and enhance the electrical conductivity by anchoring Co 1-x S and NiS nanocrystals on amorphous carbon coated multiwalled carbon nanotubes (CNTs). Benefiting from the unique structure, the Co 1-x S and NiS anodes present excellent electrochemical performances including remarkable cyclability and outstanding rate property. Furthermore, the electrochemical reaction process of the anodes is investigated by high-resolution transmission electron microscope and X-ray photoelectron spectroscopy technique. [ABSTRACT FROM AUTHOR]

ZnMn 2 O 4 mesocrystals have been fabricated through an effective, inexpensive molten salt method. Scanning electron microscopy and transmission electron microscopy observations confirm that the as-prepared ZnMn 2 O 4 nanoparticles (20–50 nm in diameter) uniformly aggregate into mesocrystals. Electrochemical investigation shows that the ZnMn 2 O 4 mesocrystals exhibit excellent cycling performance (608 mAh g −1 at 100 mA g −1 up to 100 cycles) and high rate capability. The results suggest that ZnMn 2 O 4 mesocrystal is a promising candidate for practical application as lithium ion battery anode material. [ABSTRACT FROM AUTHOR]

• NiS 1.03 @NiMoS 4 nanocrystals encapsulated into the mesoporous carbon microspheres were fabricated. • The NiS 1.03 @NiMoS 4 @C accommodates the volume change and facilitates the Li+ transport. • The NiS 1.03 @NiMoS 4 @C exhibits better electrochemical performance. Transition metal sulfides are a kind of promising anode materials for lithium batteries. However, the poor electrochemical performance originated from serious volume expansion and sluggish Li+ transport inhibit their applications. In this work, NiS 1.03 @NiMoS 4 nanocrystals encapsulated into the mesoporous carbon microspheres (NiS 1.03 @NiMoS 4 @C) are designed and synthesized through a facile hydrothermal and subsequent calcination strategy. The NiS 1.03 @NiMoS 4 @C hybrid is proven to display high reversible capacity (632 mAh g−1 after 100 cycles at 100 mA g−1), and better long-term cycle stability (435 mAh g−1 after 500 cycles at 2000 mA g−1) when evaluated as anode for lithium ion batteries. The excellent performance is attributed to the special architecture that accommodates the volume change and facilitates the Li+ transport. The present work is expected to stimulate the development of transition metal sulfides@C materials for high performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

Design and fabrication of transition metal chalcogenides hybrids for improved electrochemical performance are hotspot in materials research field. In this work, Co 0.85 Se and CuCo 2 Se 4 nanocrystals anchored on the carbon nanotubes are designed and synthesized using multifunctional carbon nanotubes as template (Co 0.85 Se/CNTs and CuCo 2 Se 4 /CNTs). The cooperation of the Co 0.85 Se and CuCo 2 Se 4 nanocrystals and the multifunctional carbon nanotubes effectively alleviate the volume variation, enhance the active reaction site and accelerate the charge transfer of Li+. Therefore, the Co 0.85 Se/CNTs and CuCo 2 Se 4 /CNTs hybrids deliver excellent electrochemical performance including superior cycle stability and high rate capacities. At high rate of 2000 mA g−1, the reversible capacities up to 566 and 479 mAh g−1 are achieved after 500 cycles. [Display omitted] • Co 0.85 Se and CuCo 2 Se 4 nanocrystals anchored on multifunctional CNTs were fabricated. • The coorperation of nanocrystals and CNTs improve the electrochemical performance. • Co 0.85 Se/CNTs and CuCo 2 Se 4 /CNTs display excellent performance at high current rate. [ABSTRACT FROM AUTHOR]

NC@NiMoS 4 nanocomposites have been firstly designed and fabricated by anchoring NiMoS 4 nanoparticles on N doped carbon nanosheets, which delivers high and stable reversible capacity and excellent rate performance. Owing to the excellent electrical conductivity and high theoretical capacity, binary transition metal sulfides have attracted extensive attention as promising anodes for lithium ion batteries (LIBs). However, the relatively poor electrical conductivity and serious capacity fading originated from large volume change still hinder their practical applications. Herein, binary NiMoS 4 nanoparticles are deposited on N doped carbon nanosheets (NC@NiMoS 4) through a facile hydrothermal method. The N doped carbon nanosheets and the strong chemical bonding between NC and NiMoS 4 can accommodate the volume change, keep the structural integrity and promote the ion/electron transfer during electrochemical reaction. The extra voids between NiMoS 4 nanoparticles enlarge the contact area and reduce the lithium migration barriers. As anode for LIBs, the NC@NiMoS 4 exhibits the excellent cycle stability with 834 mAh g−1 after 100 cycles at the current density of 100 mA g−1. Even at high rate of 2000 mA g−1, the specific capacity of 544 mAh g−1 can be achieved after 500 cycles. [ABSTRACT FROM AUTHOR]

Erythrocyte like MnCo2O4 has been synthesized using a facile solvothermal method and sintering treatment. The obtained sample is constructed by many smaller nanocrystals and possesses high surface area, which can efficiently increase the contact area for electrode/electrolyte, shorten the pathway for Li+ diffusion and buffer the volume variation during electrochemical cycling. Electrochemical investigations demonstrate that the erythrocyte like MnCo2O4 exhibits good electrochemical performance. A specific capacity of 960 mAh g−1 can be achieved after 100 cycles at the current density of 200 mA g−1. [ABSTRACT FROM AUTHOR]

• CuS nanoparticles embedded in PPy nanotubes are fabricated. • The CuS/PPy promotes Li+ ion diffusion and inhibits the aggregation of the electrode. • CuS/PPy exhibit better electrochemical performance. Copper sulfides with high electrical conductivity and theoretical capacity can be potentially applied as anode for Lithium-ion batteries (LIBs). However, some disadvantages including large volume expansion and the formation of polysulfides still exist. Herein, CuS nanocrystals embedded in the polypyrrole nanotubes are synthesized using FeOOH as sacrificial template. The unique structure can offer elastic buffer effect and restrict agglomeration and pulverization, resulting in the better electrochemical performance as anodes for LIBs. [ABSTRACT FROM AUTHOR]