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Defect engineering have profound influence on the energy storage properties of electrode hybrids by adjusting their intrinsic electronic characteristics. For iron carbide based materials, however, the effect of defect (especially cation vacancies) toward their electrochemical performance are still unclear. Herein, the feasible and scalable synthesis of Fe

We successfully designed and prepared hierarchical Ni

Defect engineering have profound influence on the energy storage properties of electrode hybrids by adjusting their intrinsic electronic characteristics. For iron carbide based materials, however, the effect of defect (especially cation vacancies) toward their electrochemical performance are still unclear. Herein, the feasible and scalable synthesis of Fe x C@NC with 3D honeycomb-like carbon architecture and abundant Fe vacancies via template etching is reported. Such structure enable outstanding lithium-ion storage properties owing to hierarchical pores, improved intrinsic electrochemical activity, as well as the introduction of more active sites. As a result, the Fe x C@NC-2 presents a high reversible specific capacity of 1079 mAh g−1 after 1000 cycles. Moreover, an excellent cycling stability can be achieved via maintaining a high-capacity retention (689 mAh g−1, 98.4%) over 1000 cycles at 5 A g−1. This study provides a feasible strategy for developing high-performance hybrids with hierarchical pore and rich defects structures.

We successfully designed and prepared hierarchical Ni3S2 nanorod@nanosheet arrays on three-dimensional Ni foam via facile hydrothermal sulfuration. We conducted a series of time- and temperature-dependent experiments to determine the Ostwald ripening process of hierarchical Ni3S2 nanorod@nanosheet arrays. The rationally hierarchical architecture creates an excellent supercapacitor electrode for Ni3S2 nanorod@nanosheet arrays. The areal capacitance of this array reaches 5.5 F cm−2 at 2 mA cm−2, which is much higher than that of Ni3S2 nanosheet arrays (1.5 F cm−2). The corresponding asymmetric supercapacitor exhibits a wide potential window of 1.6 V and energy density up to 1.0 Wh cm−2 when the proposed array is utilized as the positive electrode with activated carbon as the negative electrode. This electrochemical performance enhancement is attributable to the hierarchical structure and synergistic cooperation of macroporous Ni foam and well-aligned Ni3S2 nanorod@nanosheet arrays. Our results represent a promising approach to the preparation of hierarchical nanorod@nanosheet arrays as high-performing electrochemical capacitors.

Antimony (Sb) anode has attracted increasing attention given its high theoretical capacity and suitable working potential. Nonetheless, its practical application is largely hindered by huge volume changes during the cyclic process, resulting in unsatisfactory long-term cycled stabilities at high current density. In this work, large-scale ultrafine Sb nanoparticles are functionally designed to encapsulate into a 3D carbon microfiber framework (CMF) via a scalable electrospinning approach followed by a thermal treatment process. This fabrication strategy effectively avoids the change in the volume of the Sb anode and provides a fast conductive network to serve as an efficient 3D e/Li+ transport pathway. Benefiting from this novel structural design, an ultrafine Sb nanoparticles@carbon microfiber framework (U-Sb-NPs@CMF) composite anode used for lithium-ion batteries (LIBs) delivers a high reversible capacity of 622 mAh g-1 after 200 cycles at 0.5 A g-1 and 507 mAh g-1 after 2000 cycles at 2 Ag-1 and a high-capacity retention of 350 mAh g-1 even after 5000 long-term cycles. These outstanding charge-discharge performances suggest that the U-Sb-NPs@CMF composite is a promising candidate for an anode material in the application of LIBs.