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The rational structure design and strong interfacial bonding are crucially desired for high performance zinc oxide (ZnO)/carbon composite electrodes. In this context, micro-nano secondary structure design and strong dopamine coating strategies are adopted for the fabrication of flower-like ZnO/carbon (ZnO@C nanoflowers) composite electrodes. The results show the ZnO@C nanoflowers (2–6 μm) are assembled by hierarchical ZnO nanosheets (∼27 nm) and continuous carbon framework. The micro-nano secondary architecture can facilitate the penetration of electrolyte, shorten lithium ions diffusion length, and hinder the aggregation of the nanosheets. Moreover, the strong chemical interaction between ZnO and coating carbon layer via C-Zn bond improves structure stability as well as the electronic conductivity. As a synergistic result, when evaluated as lithium ion batteries (LIBs) anode, the ZnO@C nanoflower electrodes show high reversible capacity of ca. 1200 mA h g −1 at 0.1 A g −1 after 80 cycles. As well as good long-cycling stability (638 and 420 mA h g −1 at 1 and 5 A g −1 after 500 cycles, respectively) and excellent rate capability. Therefore, this rational design of ZnO@C nanoflowers electrode is a promising anode for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Graphical abstract A simple co-precipitation approach to fabricate the Ni-NiCo 2 O 4 @ZnCo 2 O 4 yolk-shell nano-tetrahedron composites has been developed, which significantly improve the structural stability and conductivity of composite materials and exhibit excellent cycling and rate performance for lithium ion batteries. Highlights • A Ni-NiCo 2 O 4 @ZnCo 2 O 4 yolk-shell nano-tetrahedron has been prepared. • The capacity is up to 1571.9 mA h g−1 at 0.1 A g−1. • Ni-NiCo 2 O 4 @ZnCo 2 O 4 exhibited excellent rate capability and cycle stability. • Its excellent electrochemical performance came from yolk-shell architecture and the Ni-doping. Abstract Transition-metal oxide materials have gained significant attention as high-performance anode materials for lithium ion batteries. Great advances have been achieved in the development of micro/nanostructured materials with controllable shape and tunable pore size. In this work, a facile co-precipitation approach has been developed to fabricate the Ni-NiCo 2 O 4 @ZnCo 2 O 4 yolk-shell nano-tetrahedron composites, which significantly improve the structural stability and conductivity of the material. The Ni-NiCo 2 O 4 @ZnCo 2 O 4 is proven to exhibit excellent cycling and rate performance for lithium ion batteries, such as the charge capacity of 1571.9 mA h g−1 after 70 cycles at 0.1 A g−1, 1097.5 mA h g−1 after 600 cycles at 1.0 A g−1. This superior electrochemical performance may attribute to the yolk-shell architecture and the Ni-doping. [ABSTRACT FROM AUTHOR]