NiMn-Ag NWs Complexes Electrode Material with In Situ Grown Conductive 3D Networks for Enhanced Supercapacitive Performance by Boosting Ni2+

Abstract

Power density is one of the important factors affecting the performance of electrode materials, which is hampered by ion/electron transport and agglomeration build-up problems. In this study, a novel 3D NiMnO₃/Ni(OH)₂/Ag NWs composite is synthesized via the introduction of Ag NWs. The introduction of Ag NWs synergistically influences the crystal structure and micro-morphology of the NiMnO₃/Ni(OH)₂/Ag NWs composite. The unique pentatwinned structure of Ag NWs facilitates the enhancement of the (110) and (101) crystal planes, which induces the movement of Ni 2p_3/2, leading to a significant increase of Ni²⁺ concentration in the composites. This ensures an abundance of ion adsorption sites, generating materials conducive to reactive activity. This new structure increases the density of active sites and establishes a conductive network, which optimizes the electron and ion transport paths, greatly reduces the diffusion resistance at the electrode-electrolyte interface, and improves the charge transfer efficiency, thus effectively increasing the specific capacity and energy density of the material. The NiMnO₃/Ni(OH)₂/Ag NWs//AC device exhibits a remarkable specific capacity of 350.478 mAh·g^-1 at a current density of 0.01 A·cm^-2, and its Ragone plot reveals a peak energy density of 81.107 Wh kg^-1 at a power density of 1699.871 W kg^-1. Additionally, it achieves an energy density of 60.532 Wh kg^-1 at a power density of 8490.072 W kg^-1. This study explores the design and application of 3D structured electrode materials, which effectively improves the specific capacity of the materials and provides a new idea to further improve the energy density of supercapacitors.