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Ti2 Nb 1 0 O 2 9 (TNO) is considered as a potential anode material due to its high capacity/power density and reliable safety. However, its poor electronic conductivity restricts its rate performance, which is important for its application in electric vehicles (EVs). In this study, we fabricated a hybrid of Ti2 Nb 1 0 O 2 9 − x /holey-reduced graphene oxide (TNOx/HRGO) by a two-step method. In the structure of TNOx/HRGO, TNOx microspheres with oxygen vacancies are wrapped by gossamer-like HRGO. The oxygen vacancies of TNOx and the high conductivity of HRGO can effectively enhance the electronic conductivity of the TNOx/HRGO hybrid, and the HRGO holes are beneficial for the transmission of lithium-ion ( Li + ). The synergy effect of above features improves the rate performance of the TNOx/HRGO hybrid. In addition, the existence of HRGO can buffer volume expansion during the insertion processes of Li + , which can improve cyclic stability of the TNOx/HRGO hybrid. Consequently, the TNOx/HRGO electrode has excellent lithium-ion storage capacity, with high-rate performance (242 mAh/g at 10∘C, 225 mAh/g at 20∘C and 173 mAh/g at 40∘C) and excellent cyclic stability (98.0% capacity retention after 300 cycles at 10∘C). This work reveals that TNOx/HRGO can be a potential anode material for high-rate-performance lithium-ion storage. TNOx/HRGO hybrid was fabricated through solvothermal method, annealing, and freeze-drying, and its performance as anode of LIB was investigated. Due to its porous microstructure, the existence of oxygen vacancies and holey-reduced graphene oxide coating, the electronic conductivity and ionic conductivity of TNOx/HRGO were greatly improved, thus obtaining excellent high-rate performance. [ABSTRACT FROM AUTHOR]

In this work, we report a new approach to resolve a practical problem in producing conductive polystyrene/reduced-graphene-oxide (PS/RGO) composites, i.e. the dilemma that raising the conductivity detrimentally compromises the environmental friendliness of the process because the prevalent chemistry designs emphasize raising conductivity in RGO production by employing strong and toxic chemicals or energy-consuming heat treatments. These designs then rely on organic solvents, chemical functionalization, and stabilizers to overcome the difficulty in dispersing and incorporating RGO into the polymer matrix. In our new design, we emphasize that a compact percolated three-dimensional microcellular RGO network with long-range order is the most effective use of RGO for high composite conductivity. With this guide, GO and non-polar PS mono-dispersed microspheres are co-dispersed in water, with GO stably adsorbing on the microspheres. PS/GO microspheres are then reduced with a nontoxic reducing agent such as vitamin C. PS/RGO microspheres are subsequently hot-pressed into a composite with the required compact percolated three-dimensional microcellular RGO structure. Experimental data collected from the resultant composites validate the design and indeed show low percolation threshold (0.08 vol%), high conductivity (20.5 S m−1), and good compliance with the principles of green chemistry. [ABSTRACT FROM AUTHOR]