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Developing high-capacity electrode materials is critical to enhance the energy-density of lithium-ion batteries. Here, a new graphene nanoplatelets-supported SiO x -disordered carbon composite (SiO x -C/GNPs) is fabricated by a Stöber-type process and high-temperature treatment. When used as an anode for lithium-ion batteries, SiO x -C/GNPs exhibits excellent cycle stability and rate capability even under deep charge–discharge cycling. A stable reversible capacity of about 630 mAh g −1 (calculated on the total mass of the composite) can be achieved at a current density of 100 mA g −1 and the capacity retention is nearly 100% after 250 cycles. Additionally, the plateau voltages of lithium extraction for the composite are only slightly higher than those for the commercial graphite, which ensures the high energy density of the assembled batteries. The superior electrochemical performance of this novel material is due to its unique features: excellent electronic conductivity, short transportation length for both lithium ions and electrons, elastomeric space to accommodate volume changes upon Li insertion/extraction and robust connection between SiO x and GNPs. [ABSTRACT FROM AUTHOR]

Nitrogen-doped 3D graphene frameworks (N-3D GFs) were synthesized by a facile two-step method: Polystyrene (PS) encapsulated in graphene oxide (GO) composites (denoted as PS@GO) are first synthesized, followed by a post–thermal annealing in ammonia step to get N-doped 3D GFs. The resulting N-3D GFs inherit the advantages of graphene, which possesses high electrical conductivity and high specific surface area. Furthermore, the well-defined 3D interconnected structure can facilitate the access of the electrolyte to the electrode surface, thus shortening the diffusion length of both Li + /e − , keeping the overall electrode highly conductive and active in lithium storage. Simultaneously, the in-situ formation of pyridinic N and pyrrolic N in 3D GFs provide high electronic conductivity and structure stability for lithium storage. The designed N-3D GFs electrode delivers a high specific capacity of 1094 mAhg −1 after 100 cycles at 200 mAg −1 and superior rate capability (691 mAhg −1 after 500 cycles at 1000 mAg −1 ) when used as anode for LIBs. We believe that such an inherently inexpensive, scalable, facile method can significantly increase the feasibility of building high performance energy storage system. [ABSTRACT FROM AUTHOR]