Summary
Severe mechanical degradations and sluggish ion/electron migration are challenges for developing high‐performance NiO‐based anodes. Herein, by accelerating the solidification process of eutectic precursors, bimodal porous Ni@NiO nanowire networks containing refined one‐dimensional nanowire skeleton, abundant porous structure and large number of surface oxygen defects are obtained. The well‐designed porous networks can effectively adapt to the volumetric variation of electrode during cycling. In addition, the density functional theory computation confirms that oxygen vacancies play an important role in providing superior Li capture ability, enhancing the electrical conductivity and surface reactivity. Benefiting from the above advantages, the Ni@NiO‐45 anode presents impressive cycling stability, delivering a reversible capacity of 697.9 mAh g−1 after 100 cycles at a current density of 100 mA g−1. The proposed structural regulating strategy in this study is anticipated to promote the exploitation of high‐performance conversion anodes and the application of dealloying technology in extensive fields.
As high-capacity anode materials, spinel NiFe2O4 aroused extensive attention due to its natural abundance and safe working voltage. For widespread commercialization, some drawbacks, such as rapid capacity fading and poor reversibility due to large volume variation and inferior conductivity, urgently require amelioration. In this work, NiFe2O4/NiO composites with a dual-network structure were fabricated by a simple dealloying method. Benefiting from the dual-network structure and composed of nanosheet networks and ligament-pore networks, this material provides sufficient space for volume expansion and is able to boost the rapid transfer of electrons and Li ions. As a result, the material exhibits excellent electrochemical performance, retaining 756.9 mAh g−1 at 200 mA g−1 after cycling for 100 cycles and retaining 641.1 mAh g−1 after 1000 cycles at 500 mA g−1. This work provides a facile way to prepare a novel dual-network structured spinel oxide material, which can promote the development of oxide anodes and also dealloying techniques in broad fields.
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