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The unique micro-sized (2–10 µm) Si/C composites consisting of 20 nm carbon coated secondary Si were synthesized from the abundant and low cost Al–Si alloy ingot by acid etching, ball-milling and carbonization procedure. The nano-porous Si/C composites provide a capacity of 1182 mAh g −1 at a current density of 50 mAg −1 , 952 mAh g −1 at 200 mAg −1 , 815 mAh g −1 at 500 mAg −1 , and maintain 86.8% of initial capacity after 300 cycles. Even at a much higher current density of 10 A/g, the porous Si/C anode can still provide capacities of >200 mAh g −1 . Its superior rate capability and cycling stability of micro-sized nano-porous Si/C anodes is because it takes advantage of both long cycle life of nano-Si and high volumetric/gravimetric capacity of micro-Si. The hierarchical porous micro-scale Si/C with the carbon coating can stabilize the SEI layer and the inside pore provides adequate space for Si expansion, relaxing the stress/strain. The hierarchical Si/C with exceptional electrochemical performance is prepared by a simple, low-cost and saleable synthesis method, making it very promising for a large-scale production of high-performance Si-based anode materials in high-energy lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Well dispersed chestnut-like Cd2Ge2O6 (CGO) and Cd2Ge2O6/reduced graphene oxide (CGO/RGO) nanocomposites are successfully prepared via a facile one-pot hydrothermal method and characterized as novel lithium storage materials for the first time. Electrochemical characterization of lithiation/delithiation of the CGO/RGO nanocomposites reveals a large capacity of 943mAhg−1 for the first cycle and a capacity retention of 721mAhg−1 even after 100 cycles. The superior electrochemical performance of the CGO/RGO nanocomposites electrode compared to the pure CGO electrode can be attributed to the well dispersed RGO which enhances the electronic conductivity and accommodate the volume change during the lithium storage process. [Copyright &y& Elsevier]

A novel bismuth-carbon composite, in which bismuth nanoparticles were anchored in a nitrogen-doped carbon matrix (Bi@NC), is proposed as anode for high volumetric energy density lithium ion batteries (LIBs). Bi@NC composite was synthesized via carbonization of Zn-containing zeolitic imidazolate (ZIF-8) and replacement of Zn with Bi, resulting in the N-doped carbon that was hierarchically porous and anchored with Bi nanoparticles. The matrix provides a highly electronic conductive network that facilitates the lithiation/delithiation of Bi. Additionally, it restrains aggregation of Bi nanoparticles and serves as a buffer layer to alleviate the mechanical strain of Bi nanoparticles upon Li insertion/extraction. With these contributions, Bi@NC exhibits excellent cycling stability and rate capacity compared to bare Bi nanoparticles or their simple composites with carbon. This study provides a new approach for fabricating high volumetric energy density LIBs. [ABSTRACT FROM AUTHOR]

Lithium-ion capacitors, as a hybrid electrochemical energy storage device, realize high specific energy and power density within one device, thus attracting extensive attention. Here, hierarchically porous Li 3 VO 4 /C nanocomposite is prepared by a solvo-thermal reaction, followed with a post-annealing process. This composite has macropores at the center and mesopores in the wall, thus effectively promoting electrolyte penetration and structure stability upon cycling simultaneously. Compared to mesoporous Li 3 VO 4 , the enhanced rate capability and specific capacity of hierarchically porous Li 3 VO 4 /C indicate the synergistic effect of mesopores and macropores. Inspired by these results, this composite is coupled with mesoporous carbon (CMK-3) for lithium-ion capacitors, generating a specific energy density of 105 Wh kg −1 at a power density of 188 W kg −1 . Even if the power density increases to 9.3 kW kg −1 , the energy density still remains 62 Wh kg −1 . All these results demonstrate the promising potential of hierarchically porous Li 3 VO 4 in lithium ion capacitors. [ABSTRACT FROM AUTHOR]

High electrochemical reversibility of the TiS 2 anode in “Water-in-Salt” electrolyte (21 m LiTFSI in H 2 O) is demonstrated for the first time. The wide electrochemical window and low chemical activity of H 2 O in the “Water-in-Salt” electrolyte not only significantly enhanced the electrochemical reversibility of TiS 2 but also effectively suppressed the hydrolysis side reaction in the aqueous electrolyte. Paired with a LiMn 2 O 4 cathode, the LiMn 2 O 4 /TiS 2 full cell delivers a relatively high discharge voltage of 1.7 V and an energy density of 78 Wh kg − 1 as well as a satisfactory rate performance. [ABSTRACT FROM AUTHOR]