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

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 Ni 12 P 5 @PANI core-shell structure by polyaniline cladding on the Ni 12 P 5 nanowires. The polyaniline not only effectively improves the specific capacity of Ni 12 P 5 , but also greatly enhances the cyclic stability. The optimized Ni 12 P 5 @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 Ni 12 P 5 , and the lower formation energy verifies that the polyaniline shell layer can effectively promote the structural stability of Ni 12 P 5 , thus enhancing the cycle life. In addition, the assembled Ni 12 P 5 @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. • Ni 12 P 5 @PANI core-shell structure is fabricated by cladding the Ni 12 P 5 with PANI. • Ni 12 P 5 @15PANI provides 272.8 mAh g −1 at 1 A g −1 (189.2 mAh g −1 at 10 A g −1 ). • Ni 12 P 5 @15PANI nanowires retain 93% capacity after 1000 cycles at 10 A g −1 . • The core-shell structure effectively improves the stability of Ni 12 P 5 . • Ni 12 P 5 @15PANI//Zn has 287.9 Wh kg −1 and 112.3% capacity retention at 3 A g −1 .