Enhanced polymerization interface of Ni12P5 nanowires toward high-rate and durable cathode for alkaline Ni–Zn batteries

Abstract

Alkaline nickel-zinc batteries have attracted more attention due to their inherent safety and high specific energy. However, the cycling stability of Ni–Zn batteries is still an urgent problem. Herein, we fabricate the Ni12P5@PANI core-shell structure by polyaniline cladding on the Ni12P5 nanowires. The polyaniline not only effectively improves the specific capacity of Ni12P5, but also greatly enhances the cyclic stability. The optimized Ni12P5@PANI nanowires provide a specific capacity of 272.8 mAh g−1 at 1 A g−1 (189.2 mAh g−1 at 10 A g−1, 69.4% retention rate) and long-life cycling (93% capacity retention after 1000 cycles at 10 A g−1). Moreover, the theoretical calculations indicate that the polyaniline is easy to polymerize on the surface of Ni12P5, and the lower formation energy verifies that the polyaniline shell layer can effectively promote the structural stability of Ni12P5, thus enhancing the cycle life. In addition, the assembled Ni12P5@PANI//Zn battery retains 112.3% capacity retention after 500 cycles at 3 A g−1, and provides a high energy density of 287.9 Wh kg−1 and power density of 49.1 kW kg−1 (based on the mass of active substance). This work provides a feasible high-rate and durable cathode material for alkaline Ni–Zn batteries.