Strong Magnetic-Field-Engineered Porous Template for Fabricating Hierarchical Porous Ni–Co–Zn–P Nanoplate Arrays as Battery-Type Electrodes of Advanced All-Solid-State Supercapacitors
Lu Liu, Xing Yu, Weiwei Zhang, Qingyun Lv, Long Hou, Yves Fautrelle, Zhongming Ren, Guanghui Cao, Xionggang Lu, Xi Li
Abstract
The sluggish charge transport kinetics that exist in the energy storage process of all-solid-state supercapacitors (ASSSCs) can be improved by designing open hierarchical porous structures for binder-free electrodes. Herein, a template-directed strategy is developed to fabricate open hierarchical porous Ni–Co–Zn–P nanoplate arrays (NCZP6T) through phosphating the electrodeposited NiCo–LDH nanosheets loaded on a template. At first, porous conductive NiZn alloy nanoplate arrays are rationally devised as the template by a strong magnetic field (SMF)-assisted electrodeposition. The Lorentz force caused by coupling the SMF with the electrical current induces a magnetohydrodynamic (MHD) flow (including the micro-MHD flow), which homogenizes the deposition coating, tunes the nucleation and growth of the NiZn alloy, and produces pores in the nanoplates. The open hierarchical porous structure offers a larger specific surface area and pore volume for accelerating charge transport and gives a synergistic effect between the inner porous conductive NiZn array template and the outer electrochemical active phosphides for high-performance hybrid ASSSCs. Accordingly, the battery-type electrode of NCZP6T shows a much higher specific capacitance of 3.81 F cm–2 at 1 mA cm–2, enhanced rate capability, and remarkable cycling stability at progressively varying current densities. Finally, the NCZP6T//FeS ASSSC delivers a high energy density of 77 μW h cm–2 at a large power density of 12 mW cm–2, outperforming most state-of-the-art supercapacitors.