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Highlights: [•] Co3O4 nanocrystals with size of 20nm homogeneously embedded in the carbon matrix are successfully synthesized. [•] Cycle exceeds 400 times in half cells at a 5C (5 Ag−1) rate while retaining about 1000 mAhg−1 reversible capacities. [•] Large rates up to 10C for are achieved with high energy density. [•] Such Co3O4 exhibits excellent high-rate capability and cycling stability. [Copyright &y& Elsevier]

Abstract: As a high-theoretical-capacity (782mA hg-1), low-cost and low-toxicity material, SnO2 has attracted intense interest for use as an anode electrode for lithium-ion batteries (LIBs). Despite intensive study, the practical use of SnO2-based anodes is hindered by their poor capacity retention and low rate capacity resulting from their large specific-volume changes and kinetic limitations in ion/electron transfer during the lithium ion insertion/extraction process. Improving the performance of SnO2-based electrodes has become one of the most popular scientific and industrial efforts. Herein, we present a type of SnO2-graphene composite anode in which SnO2 nanoparticles are uniformly anchored on both sides of vertically aligned graphene nanosheets (SnO2-VAGN-SnO2). The VAGNs sandwiched by the nanoparticles can supply rapid ion and electron transport pathways for Li+ and e-. Such integrated electrodes exhibit high specific capacity and excellent cycling stability, even at high current densities. The cells can cycle more than 5,000 times and retain a reversible capacity of 210mA h g-1 at 9 A g-1. A high current density of up to 20 A g-1 is achieved, and the power and energy density can reach 1576.75W kg-1 and 110.14 Wh kg-1, respectively. These performances indicate that the composite could offer the advantages of both LIBs (high energy density) and supercapacitors (high power density). [Copyright &y& Elsevier]

Abstract: A facile way towards high rate and long lifespan anode materials based on SnO2 and commercial multiwalled carbon nanotubes (MWCNTs) is readily achieved through a combination of activation and hydrothermal treatment. The former endows the MWCNTs with abundant hydrophilic radicals, while the latter guarantees intimate connection between SnO2 and MWCNTs; eventually, monodisperse SnO2 nanocrystals ca. 3nm are firmly anchored on the MWCNTs without agglomeration. When used for lithium ion batteries (LIBs) anodes, the hybrid composite exhibits excellent cycling capability with high reversible capacity about 700 mAh g−1 (based on total weight of the composite) for 150 cycles at 0.1 A g−1 superior to both components involved. Besides large rates of 5 A g−1 with recoverable initial reversible capacity, it also last for more than 1000 cycles with little capacity decay, outperforming most SnO2 based carbon nanotubes composites (SnO2/CNTs) so far. Insights into the electrochemical processes reveal the hybrid composite exhibits enhanced redox capacitance and interfacial capacitance in comparison with SnO2 nanocrystals which indicate the perfect interfaces and robust structure of the hybrid composite. [Copyright &y& Elsevier]