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Developing suitable electrode materials for electrochemical energy storage devices by biomorph assisted design has become a fascinating topic due to the fantastic properties derived from bio-architectures. Herein, zephyranthes-like Co2NiSe4 arrays grown on butterfly wings derived three-dimensional (3D) carbon framework (Z-Co2NiSe4/BWC) is fabricated via hydrothermal assembly and further conversion method. Benefiting from its unique structure and multi-components, the obtained Z-Co2NiSe4/BWC electrode for supercapacitor delivers an excellent specific capacitance of 2,280 F·g−1 at 1 A·g−1. Impressively, the constructed asymmetric supercapacitor using Co2NiSe4/BWC as positive electrode and activated butterfly wings carbon as negative electrode acquires a high energy density of 42.9 Wh·kg−1 at a power density of 800 W·kg−1 with robust stability of 94.6% capacitance retention at 10 A·g−1 after 5,000 cycles. Moreover, the Z-Co2NiSe4/BWC as anode for sodium-ion batteries exhibits a high specific capacity of 568 mAh·g−1 at 0.1 A·g−1 and high cycling stability (maintaining 80.1% of the second cycle after 100 cycles). The outstanding electrochemical performances are ascribed to that the synergistic effect of bimetallic selenides and N-doped carbon improves electrochemical activities and conductivity. One-dimensional (1D) nanoneedles grown on 3D porous framework increase the exposure of redox-active sites, endow adequate transmission channels of electrons/ions, and guarantee stability of the electrode during charge/discharge processes. This study will shed light on the avenue towards extending such nanohybrids to excellent energy storage applications. [ABSTRACT FROM AUTHOR]

To overcome the low electrical conductivity weakness of layered double hydroxide and to improve the electrochemical energy storage performance as supercapacitor electrodes, NiAl layered double hydroxide (NiAl‐LDH) flowers with ultrathin structure grown on three‐dimensional graphene (3DG) was constructed via a facile hydrothermal strategy. The NiAl‐LDH/3DG composites as binder‐free supercapacitor electrode showed a high specific capacitance of 884.5 F g–1 at 1 A g–1. Excellent cycle stability retaining 90 % of the initial capacitance after 7000 cycles at 5 A g–1 was also demonstrated, with the coulombic efficiency stayed above 95 % during the whole cycling process. The excellent performances should be ascribed to the synergistic effect of NiAl‐LDH and 3DG, in which the NiAl‐LDH ultrathin nanoflake petals provide sufficient pseudocapacitive sites; while 3DG provides robust and highly interconnected skeleton for efficient mass/charge transport. [ABSTRACT FROM AUTHOR]

Abstract Transition metal oxides have received considerable attention as promising electrode materials for the next generation high performance lithium-ion batteries and supercapacitors. However, transition metal oxides electrodes usually suffer from severe volume expansion and poor electrical conductivity, leading to fast capacity fading and low rate capability, which limit their commercialization in energy storage devices. Herein, we develop a bifunctional ZnO NiO microsphere electrode with yolk-shelled structure for lithium-ion batteries and supercapacitors by annealing tetracyanide-metallic-frameworks precursor of Zn[Ni(CN) 4 ]. Benefiting from its unique structure and composition, the yolk-shelled ZnO NiO microspheres as anode for lithium-ion batteries exhibits a high lithium storage capacity (978 mAh g−1 at 0.25 C) and superior rate performance (628 mAh g−1 at 2.5 C after 300 cycles). While for supercapacitors electrode, it delivers a high specific capacitance of 1350 F g−1 at a current density of 3.0 A g−1 and an excellent cycling stability with a capacity retention of 92.8% over 6000 cycles. The excellent electrochemical performance is ascribed to the synergistic effect between ZnO and NiO, and the yolk-shelled structure, which can provide rich active sites for electrochemical reaction, and effectively alleviate the volume expansion and structural pulverization of the electrode during charge-discharge cycling. Graphical abstract Image 1 Highlights • Yolk-shelled ZnO NiO bifunctional electrode was prepared by Zn[Ni(CN) 4 ] precursor. • It shows enhanced cycle performances with 628 mAh g−1 at 2.5 C after 300 cycles. • It exhibits high specific capacitance and an ultralong cycling lifetime for SCs. • The excellent performance is due to the unique structure and synergistic effect. [ABSTRACT FROM AUTHOR]