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Although high-temperature solid-phase methods have become the dominant route for manufacturing layered oxide cathode materials in industry, severe Li+/Ni2+ cation mixing problems caused by high-temperature processes still prevent the realization of high-performance lithium-ion batteries. Herein, a wet chemical lithiation method by stepwise lithium intercalation to reduce and shorten the sintering temperature and time of the post-treatment process is proposed. Li 0.6 H x Ni 0.52 Co 0.19 Mn 0.29 O 2 stepwise products with lithiation efficiencies exceeding 60% were obtained at reaction temperatures below 200 °C. The as-prepared LiNi 0.52 Co 0.19 Mn 0.29 O 2 (HT-52-S) exhibits low Li+/Ni2+ cation mixing and good comprehensive electrochemical performance after subsequent heat treatment to complete all lithiation. Compared with LiNi 0.52 Co 0.19 Mn 0.29 O 2 (SS-52) prepared by the conventional high-temperature solid-phase method, the Li+/Ni2+ cation mixing of HT-52-S was relatively reduced by 57.9%, and the capacity retention after 100 cycles at 1 C was relatively improved by 22.1%. We believe that this work can serve as a useful reference to develop manufacturing processes for high-performance layered oxide cathode materials. [ABSTRACT FROM AUTHOR]

Reasonable design of multi-component metal oxides hierarchical nanostructures is an effective and promising way to improve electrochemical performances of electrode materials. In this work, novel hydrangea-like ZnCo 2 O 4 /Ni 3 V 2 O 8 hierarchical nanostructures are constructed by adjusting the ratio of ZnCo 2 O 4 and Ni 3 V 2 O 8. The perfect architecture maximizes the synergistic effect between different components and provides abundant electrochemical reactive sites, promoting the diffusion and transfer of electrolyte ions in electrochemical reaction process. As a result, ZnCo 2 O 4 /Ni 3 V 2 O 8 electrodes deliver an enhanced specific capacitance of 1734 F g−1 at 1 A g−1 and cyclic stability (96% of initial capacitance is retained after 8000 cycles). Furthermore, the assembled ZnCo 2 O 4 /Ni 3 V 2 O 8 //AC device e achieves excellent energy density of 90 Wh kg−1 at power density of 812 W kg−1, proving the optimized hydrangea-like ZnCo 2 O 4 /Ni 3 V 2 O 8 hierarchical nanostructures are promising electrode material for supercapacitor. In addition, this work supplies helpful insights into rational design of structure and composition of multi-component metal oxides for enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Flower-like ZnO–NiO mesoporous architectures were synthesized through annealing the zinc hydroxide carbonate–nickel hydroxide carbonate composite precursor, which was prepared via a one-pot hydrothermal route. More importantly, we successfully prepared flower-like porous ZnO–NiO/graphene composites by introducing flexible graphene into the flower-like porous ZnO–NiO. In addition, we explore the application of the 3D flower-like ZnO–NiO composite mesoporous architectures and flower-like porous ZnO–NiO/graphene composites as anode materials for lithium ion battery. Electrochemical study presented that the as-prepared flower-like porous ZnO–NiO/graphene composites demonstrate excellent electrochemical performance and cycling stability. The first discharge capacity is 1205.7 mA h/g at a high current density of 300 mA/g. After 50 cycles, the reversible capacity is 452.7 mA h/g at a current density of 300 mA/g and the coulomb efficiency reaches at 99%.The improved electrochemical performances are mainly attributed to its morphological characteristics of mesoporous, nanosheet self-assembling architectures, as well as the addition of graphene. These results suggest that such 3D flower-like porous ZnO–NiO/graphene composites are promising materials for lithium ion battery. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) graphene@CNTs@MnO 2 (GCM) nanocomposites materials have been fabricated by a facile two-step method. The structure, morphology and electrochemical properties of the 3D nanocomposites were investigated by XRD, TG, Raman, SEM, TEM and electrochemical measurements. The 3D forest-like rGO@CNTs (GC) serves as both the backbone and ideal electron pathway for MnO 2 . With this sophisticated configuration, the 3D GCM nanocomposites exhibit a specific capacitance of 245 F g −1 at 0.5 A g −1 , excellent cycling stability (91.4% retention after 2000 cycles at 1 A g −1 ) and high rate capability. These excellent capacitive performances may make the as-prepared nanocomposites as promising electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]