Layered SnS2-reduced graphene oxide composite--a high-capacity, high-rate, and long-cycle life sodium-ion battery anode material.

A layered SnS -reduced graphene oxide (SnS -RGO) composite is prepared by a facile hydrothermal route and evaluated as an anode material for sodium-ion batteries (NIBs). The measured electrochemical properties are a high charge specific capacity (630 mAh g at 0.2 A g ) coupled to a good rate performance (544 mAh g at 2 A g ) and long cycle-life (500 mAh g at 1 A g for 400 cycles). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 2 2 -1 -1 -1 -1 -1 -

Engineering oxygen vacancies in hierarchically Li-rich layered oxide porous microspheres for high-rate lithium ion battery cathode

Abstract(#br)Lithium-rich layered oxides always suffer from low initial Coulombic efficiency, poor rate capability and rapid voltage fading. Herein, engineering oxygen vacancies in hierarchically Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 porous microspheres (L@S) is carried out to suppress the formation of irreversible Li 2 O during the initial discharge process and improve the Li + diffusion kinetics and structural stability of the cathode mateiral. As a result, the prepared L@S cathode delivers high initial Coulombic efficiency of 92.3% and large specific capacity of 292.6 mA h g −1 at 0.1 C. More importantly, a large reversible capacity of 222 mA h g −1 with a capacity retention of 95.7% can be obtained after 100 cycles at 10 C. Even cycled at ultrahigh rate of 20 C, the L@S cathode can..

Surface Ni-rich engineering towards highly stable Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode materials

Abstract(#br)Li-rich layered oxide cathode materials (LLOs) are regarded as promising next-generation cathode candidate in high-energy-density lithium ion batteries due to their high specific capacity over 250 mA h g −1 . However, LLOs always suffer from a series of severe issues, such as rapid voltage fading, fast capacity decay and bad cycling stability. In this work, Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 -Li 1.2 Mn 0.44 Ni 0.32 Co 0.04 O 2 (LLO-111@111/811) hybrid layered-layered cathode is constructed via facilely increasing surface Ni content. Profiting from this special design, the prepared LLO-111@111/811 cathode exhibits a remarkable specific capacity of 249 mA h g −1 with a high capacity retention of 89.3% and a high discharge voltage of 3.57 V with a voltage retention of 83.0% after cycling 350 times at 0.5 C. As a result, the specific energy of LLO-111@111/811 cathode is 887 Wh Kg −1 at 0.5 C and it keeps as high as 658 Wh Kg −1 after 350 cycles. LLO-111@111/811 also exhibits an initial high capacity of 169 mA h g −1 at a high rate of 5 C and maintains a good capacity retention of 90.0% after 200 cycles. This strategy can successfully improve structural stability, suppress capacity decay and restrain voltage fading of LLOs, which is beneficial for their practical application

High Initial Reversible Capacity and Long Life of Ternary SnO2‑Co‑carbon Nanocomposite Anodes for Lithium‑Ion Batteries

The two major limitations in the application of SnO2 for lithium-ion battery (LIB) anodes are the large volume variations of SnO2 during repeated lithiation/delithiation processes and a large irreversible capacity loss during the first cycle, which can lead to a rapid capacity fade and unsatisfactory initial Coulombic efficiency (ICE). To overcome these limitations, we developed composites of ultrafine SnO2 nanoparticles and in situ formed Co(CoSn) nanocrystals embedded in an N-doped carbon matrix using a Co-based metal–organic framework (ZIF-67). The formed Co additives and structural advantages of the carbon-confined SnO2/ Co nanocomposite effectively inhibited Sn coarsening in the lithiated SnO2 and mitigated its structural degradation while facilitating fast electronic transport and facile ionic diffusion. As a result, the electrodes demonstrated high ICE (82.2%), outstanding rate capability (~ 800 mAh g−1 at a high current density of 5 A g−1), and long-term cycling stability (~ 760 mAh g−1 after 400 cycles at a current density of 0.5 A g−1). This study will be helpful in developing high-performance Si (Sn)-based oxide, Sn/Sb-based sulfide, or selenide electrodes for LIBs. In addition, some metal organic frameworks similar to ZIF-67 can also be used as composite templates

Layered SnS2-reduced graphene oxide composite--a high-capacity, high-rate, and long-cycle life sodium-ion battery anode material.

A layered SnS2-reduced graphene oxide (SnS2-RGO) composite is prepared by a facile hydrothermal route and evaluated as an anode material for sodium-ion batteries (NIBs). The measured electrochemical properties are a high charge specific capacity (630 mAh g-1 at 0.2 A g-1) coupled to a good rate performance (544 mAh g-1 at 2 A g-1) and long cycle-life (500 mAh g-1 at 1 A g -1 for 400 cycles). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Co₃O₄@(Fe-Doped)Co(OH)₂ Microfibers: Facile Synthesis, Oriented-Assembly, Formation Mechanism, and High Electrocatalytic Activity

Cobalt oxide or hydroxide nanoarchitectures, often synthesized via solvothermal or electrodeposition or templated approaches, have wide technological applications owing to their inherent electrochemical activity and unique magnetic responsive properties. Herein, by revisiting the well-studied aqueous system of Co/NaBH₄ at room temperature, the chainlike assembly of Co₃O₄ nanoparticles is attained with the assistance of an external magnetic field; more importantly, a one-dimensional hierarchical array consisting of perpendicularly oriented and interconnected Co­(OH)₂ thin nanosheets could be constructed upon such well-aligned Co₃O₄ assembly, generating biphasic core–shell-structured Co₃O₄@Co­(OH)₂ microfibers with permanent structural integrity even upon the removal of the external magnetic field; isomorphous doping was also introduced to produce Co₃O₄@Fe–Co­(OH)₂ microfibers with similar structural merits. The cobalt-chemistry in such a Co/NaBH₄ aqueous system was illustrated to reveal the compositional and morphological evolutions of the cobalt species and the formation mechanism of the microfibers. Owing to the presence of Co₃O₄ as the core, such anisotropic Co₃O₄@(Fe-doped)­Co­(OH)₂ microfibers demonstrated interesting magnetic-responsive behaviors, which could undergo macro-scale oriented-assembly in response to a magnetic stimulus; and with the presence of a hierarchical array of weakly crystallized thin (Fe-doped) Co­(OH)₂ nanosheets with polycrystallinity as the shell, such microfibers demonstrated remarkable electrocatalytic activity toward oxygen evolution reactions in alkaline conditions

High Initial Reversible Capacity and Long Life of Ternary SnO2-Co-carbon Nanocomposite Anodes for Lithium-Ion Batteries

Abstract The two major limitations in the application of SnO2 for lithium-ion battery (LIB) anodes are the large volume variations of SnO2 during repeated lithiation/delithiation processes and a large irreversible capacity loss during the first cycle, which can lead to a rapid capacity fade and unsatisfactory initial Coulombic efficiency (ICE). To overcome these limitations, we developed composites of ultrafine SnO2 nanoparticles and in situ formed Co(CoSn) nanocrystals embedded in an N-doped carbon matrix using a Co-based metal–organic framework (ZIF-67). The formed Co additives and structural advantages of the carbon-confined SnO2/Co nanocomposite effectively inhibited Sn coarsening in the lithiated SnO2 and mitigated its structural degradation while facilitating fast electronic transport and facile ionic diffusion. As a result, the electrodes demonstrated high ICE (82.2%), outstanding rate capability (~ 800 mAh g−1 at a high current density of 5 A g−1), and long-term cycling stability (~ 760 mAh g−1 after 400 cycles at a current density of 0.5 A g−1). This study will be helpful in developing high-performance Si (Sn)-based oxide, Sn/Sb-based sulfide, or selenide electrodes for LIBs. In addition, some metal organic frameworks similar to ZIF-67 can also be used as composite templates

A 3D Network of Graphene/Silicon/Graphene Sandwich Sheets as Anode for Li-Ion Battery

A freestanding 3D network strucutre of graphene/Si/graphene designed & fabricated. Coloumbic efficiency of the first de-/liathiation cycle over 80%. Stable areal capacities up to 0.62 mAh cm-2 were achieved.Anodes maitained interconnected, superlight, flexible structures after 1000 cycles.</p