Hierarchical Ni2P@Ni(OH)2 architectures supported on carbon cloth as battery-type electrodes for hybrid supercapacitors with boosting specific capacitance and cycle stability

In this work, a novel binder-free electrode, in which three-dimensional porous Ni2P@Ni(OH)2 nanosheet arrays were in situ grown on carbon cloth (CC), is rationally designed for supercapacitor applications. In comparison with Ni2P@CC, the Ni2P@Ni(OH)2@CC electrode represents superior electrochemical characteristics: the gravimetric capacitance and areal capacitance are boosted to be 632 C g−1 and 0.73 C cm−2 at 1 mA cm−2, about 2 and 2.7 times larger than those of Ni2P@CC (321 C g−1 and 0.27 C cm−2), respectively; the rate capability is improved to be 63.3% from 1 to 10 mA cm−2, about 1.5 times larger than Ni2P@CC (42.9%); the cycle stability is enhanced to be 81.4% after 1000 cycles, about 1.6 times larger than Ni2P/CC (51.8%). The assembly Ni2P@Ni(OH)2@CC//AC hybrid supercapacitor device shows high energy density of 23.5 Wh kg−1 at a power density of 1158.0 W kg−1 and good cycling stability of 75.2% maintenance after 5000 cycles. Benefiting from the combined advantages of high electronic conductivity and large specific capacitance of Ni2P, superior anion exchanging/intercalating capacity of Ni(OH)2, excellent flexibility of carbon cloth, and special hierarchical architecture with large surface area, the Ni2P@Ni(OH)2@CC electrode is promised to be a good candidate for supercapacitors.