Ni(OH)2/NiMoO4 nanoplates for large-scale fully-printed flexible solid-state supercapacitors

The increasing development demand of wearable electronics for intelligent life accelerates the studies and explorations on portable flexible energy storage system. However, how to achieve high performance power sources on a par with uncomplicated and high-efficient fabrication processes also is a huge challenge. Herein, Ni(OH)2/NiMoO4 composites with enhanced specific capacitance and cyclic lifespan are synthesized via a facile hydrothermal method. And the composites are used as functional inks for the fabrication of printed electrode of flexible solid-state supercapacitors. Large specific capacitance of 1547.3 F g−1 is achieved by the composite electrode at 1 A g−1. After charging and discharging 1000 times, 88.1% of the initial capacitance at 20 A g−1 can be retained. Large-scale flexible solid-state supercapacitors are developed through fully screen printing technique in a very short time, which exhibit high stability (115% capacitance retention after 5000 cycles) and good flexibility (81.7% of capacitance remained after 750 bending/releasing cycles). Moreover, when three printed supercapacitors are connected in series, a yellow light emitting diode (1.9 V) can be easily lighted up, which is preconceived to be a promising portable energy storage system in future wearable electronics.