Mesoporous NH₄NiPO₄·H₂O for High-Performance Flexible All-Solid-State Asymmetric Supercapacitors

Nowadays, wearable energy storage devices have been growing rapidly, but flexible systems with both excellent cycling stability and decent flexibility are still challenging. In this work, a flexible all-solid-state NH₄NiPO₄·H₂O//graphene supercapacitor with remarkable performance was successfully assembled. When cycled at a current density of 5 mA cm^-2, the device delivered 121 mF cm^-2, and showed good cycling stability after 3,000 cycles. Moreover, the all-solid-state NH₄NiPO₄·H₂O//graphene supercapacitor also exhibit high mechanical flexibility with well-maintained specific capacitance, even under bending to arbitrary angles (up to 180°) and different weights (up to 50 g).