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[Display omitted] • The yolk-shell NiO/NiSe 2 @C was prepared by carbonization, selenization and oxidation of MOF precursor. • The NiO/NiSe 2 @C exhibits a high specific capacity of 992 mAh g−1 for 600 cycles at 0.2 A g−1. • DFT shows that the heterointerface is formed which enhanced the electrochemical properties. Biphasic or multiphase heterostructures have promising futures in advanced electrode materials for energy-related applications because of their desirable synergistic effects. Here we prepared a rational NiO/NiSe 2 @C heterostructure microsphere through carbonization, selenization, and oxidation using Ni-MOF as a precursor. Electrochemical studies were conducted to examine the Li+ storage characteristics, and density functional theory (DFT) was utilized to comprehend the underlying mechanism. When employed as the anode for LIBs, the NiO/NiSe 2 @C showed a high specific capacity and long-term cyclic stability, with a specific capacity of 992 mAh g−1 for 600 cycles at a current density of 0.2 A g−1. The NiO/NiSe 2 @C exhibits a significantly enhanced lithium-ion diffusion coefficient (D Li + ) value. The DFT results show that an electron-rich area forms at the NiO/NiSe 2 heterointerface, where the metalloid selenium transfers electrons to the oxygen atoms. The lithiation reactions were improved dramatically by redistributing interfacial charges, which can trigger a built-in electric field that dramatically promotes the capacitance contribution of electrode materials, enhances the lithium storage capacity, and accelerates the ion/electron transmission. The rational synthesis of NiO/NiSe 2 @C heterostructure can provide an idea for designing novel heterostructure anode materials. [ABSTRACT FROM AUTHOR]

Spinel structured α-LiFe 5 O 8 were prepared via ball milling combined with a straightforward solid-phase method, using Fe 2 O 3 and Li 2 CO 3 as the raw materials. The material maintained a stable capacity of 440 mAh g−1 after 200 cycles at 900 mA g−1 with Coulomb efficiency more than 95 % and also showed facile lithium ion diffusion dynamics. The calculated diffusion coefficient of α-LiFe5O8 ranged around 10−10-10−12 cm2 s−1. Diffusion controlled contribution was dominant over capacitive contribution in the sweeping range 0.1–1.5 mV s−1. A new intercalation-decomposition-conversion mechanism was proposed on the basis that there existed a small pit at the initial stage of the discharge plateau and a significantly low initial discharge plateau voltage was observed compared with the followed discharge cycles. Based on the DFT calculations and the phase diagram of the Li–Fe–O system, we supposed that for the initial discharge of the material, after 1 mol of lithium ion intercalation per unit formula, α-LiFe 5 O 8 decomposed to LiFeO 2 and Fe 3 O 4. The followed discharge was the conversion of both LiFeO 2 and Fe 3 O 4 to metal Fe and Li 2 O. Thereafter, the system cycled between Fe 2 O 3 at the fully charged state and metal Fe and Li 2 O at the fully discharged state. Li–Fe–O phase diagram used to disclose the conversion mechanism. [Display omitted] • Unmodified α-LiFe 5 O 8 show good electro-chemical performance. • Li+ transportation kinetics reveals the features of fast ion conductor. • A new intercalation-decomposition-conversion mechanism was proposed. [ABSTRACT FROM AUTHOR]

The stacked Cu 2−x Se nanoplates with the interlayer spacing of ~1.8 nm were fabricated with the assistance of diethylenetriamine. Such unique nanostructures provide the 2D nanochannels for accelerating the Li-ion transport and buffering the volume change during charge-discharge process, endowing the excellent electrochemical performance. Transition metal chalcogenides are considered as promising alternative materials for lithium-ion batteries owing to their relatively high theoretical capacity. However, poor cycle stability combined with low rate capacity still hinders their practical applications. In this work, the Cu-N chemical bonding directed the stacking Cu 2−x Se nanoplates (DETA-Cu 2−x Se) is developed to solve this issue. Such unique structure with small nanochannels can enhance the reactive site, facilitate the Li-ion transport as well as inhibit the structural collapse. Benefitting of these advantages, the DETA-Cu 2−x Se exhibits high specific capacity, better rate capacity and long cyclability with the specific capacities of 565 mAh g−1 after 100 cycles at 200 mA g−1 and 368 mAh g−1 after 500 cycles at 5000 mA g−1. This novel DETA-Cu 2−x Se structure with nanochannels is promising for next generation energy storage and the synthetic process can be extended to fabricate other transition metal chalcogenides with similar structure. [ABSTRACT FROM AUTHOR]

CaMnO 3 , a perovskite-type material, has been introduced as a novel anode material for lithium ion batteries, and its electrochemical performance at different temperatures is systematically investigated. The as-prepared CaMnO 3 material exhibits a high specific capacity, favorable rate performance and excellent cycling stability. The CaMnO 3 anode could deliver a high specific capacity of 102.5 mAh g-1 after 500 cycles at a current rate of 0.1 A g-1. Lithium ion batteries are attracting ever increasing attention due to their advantages of high energy/ power density, environmental friendly, lifetime and low cost. As a star in the field of materials and energy, perovskites have received extensive attention due to their attracting physical and chemical properties. Herein, CaMnO 3 , one material from the perovskite family is introduced as a novel anode material for lithium ion batteries, and its electrochemical performance at different temperatures is systematically investigated. CaMnO 3 has been synthesized using a liquid phase synthesis method followed by high temperature calcination. The as-obtained CaMnO 3 exhibits an initial high discharge capacity of 708.4 mAh g−1, superior rate capability and stable cycling performance at room temperature, the specific capacity is 102.5 mAh g−1 after 500 cycles at a current density of 0.1 A g−1. Additionally, at an extreme temperature of 0 °C, the discapacity can reach 138.2 mAh g−1 at a current density of 0.05 A g−1. At high temperature of 50 °C, the reversible discharge capacity is up to 216.5 mAh g−1under the same condition. It is believed that this contribution may lay the foundation for the application of perovskites in other rechargeable batteries and energy storage devices. [ABSTRACT FROM AUTHOR]

The Co 0.85 Se nanosheets with the interlayer spacing of ~1.0 nm on N-doped carbon nanosheets were fabricated with the assistance of diethylenetriamine. Such unique nanostructures provide the more channels for accelerating the Li-ion transport and buffering the volume change during charge-discharge process, endowing the excellent electrochemical performance. Co 0.85 Se nanosheets assembled layer by layer on N-doped carbon nanosheets (NC@Co 0.85 Se) are designed and fabricated through a facile solvothermal process. The hexamethylenetetramine as the solvent and complexing agent promotes the accumulation of Co 0.85 Se layer by layer. The long chain diethylenetriamine between the Co 0.85 Se nanosheets provides buffer space and nanochannels for accelerating the Li+ transportation. The N-doped carbon nansheets in NC@Co 0.85 Se provide effective conductive network during charge-discharge process. As an anode material for lithium-ion batteries, the NC@Co 0.85 Se nanocomposites deliver a high specific capacity of 636 mAh g−1 after 100 cycles at current density of 200 mA g−1, and 399 mAh g−1 for 500 cycles at high current density of 5000 mA g−1. [ABSTRACT FROM AUTHOR]

Graphical abstract Porous core-shelled Sn/Sn 4 P 3 @C composite is easily fabricated by electrochemically etching SnP alloy followed by covering the uniform carbon layer, which shows superior lithium-storage performances with higher specific capacity, much enhanced rate capability, as well as better cycling stability compared with pure porous Sn 4 P 3. The Sn/Sn 4 P 3 @C material holds promising application potential as an alternative anode in the lithium storage fields. Abstract Carbon encapsulated porous Sn/Sn 4 P 3 (Sn/Sn 4 P 3 @C) composite is conveniently prepared by one-step electrochemical dealloying of Sn 80 P 20 alloy in mild conditions followed by growing one carbon layer. Controllable dealloying of the Sn 80 P 20 alloy results in the formation of bicontinuous spongy Sn 4 P 3 nanostructure with a part of residued metallic Sn atoms embedded in the porous skeleton. A uniform carbon layer is deposited on the nanoporous Sn/Sn 4 P 3 to prevent the nanostructure's pulverizing and agglomerating during lithium ion insertion/extraction. Upon double conductivity modification from metallic Sn matrix and carbon layer, the as-made composite displays superior lithium-storage performances with much higher specific capacity as well as better cycling stability compared with pure porous Sn 4 P 3. It offers a specific capacity of 837 mA h g−1 after 100 cycles at a rate of 100 mA g−1. Even after 700 cycles at the higher rate of 1000 mA g−1, the specific capacity still maintains as high as 589 mA h g−1. The Sn/Sn 4 P 3 @C material possesses promising application potential as an alternative anode in the lithium storage fields. [ABSTRACT FROM AUTHOR]

Abstract: In this manuscript, porous Co3O4 nanorods are prepared through a two-step approach which is composed of hydrothermal process and heating treatment as high performance anode for lithium-ion battery. Benefiting from the porous structure and 1-dimensional features, the product becomes robust and exhibits high reversible capability, good cycling performance, and excellent rate performance. [Copyright &y& Elsevier]

Cobalt sulfide-based electrode materials were believed to have bright future in lithium-ion batteries (LIBs) application for their high theoretical capacity and excellent electrochemical stability. However, their relatively low electronic conductivity and the large volume variation during lithiation/delithiation processes usually result in low rate capability and short cycling life. Herein, a novel mesoporous Co 1-x S/N,S-codoped carbon (Co 1-x S/N,S–C) composite was prepared by direct pyrolysis of a cobalt-2-mercaptobenzothiazole (CoMBT) complex. High-content (91.14 ​wt%) and ultrafine (∼10 ​nm) Co 1-x S nanocrystals were in-situ generated and composited with high conductive N,S-codoped carbon. The Co 1-x S/N,S–C demonstrates superior Li+-ion storage performance, delivering high discharge capacities of 1207 ​mAh g−1 at 200 ​mA ​g−1 after 50 cycles and 425 ​mAh g−1 at 5 ​A ​g−1 after 1000 cycles. [Display omitted] • A metal-organomecapto complex derived strategy was developed. • A novel mesoporous Co 1-x S/N,S-codoped carbon composite was prepared. • The composite exhibits superior lithium storage performance. [ABSTRACT FROM AUTHOR]