When hydroxyapatite nanoparticles are included in the mesoporous scaffold for perovskite solar cells they not only improve the power conversion efficiency but sequester released Pb if broken cells are immersed in water.

Most reported pristine phosphates, such as NHMPO·HO (M = Co, Ni), are not very stable as supercapacitor electrodes because of their chemical properties. In this work, KCoNiPO·HO microplates were fabricated by a facile hydrothermal method at low temperature and used as electrodes in supercapacitors. The Co and Ni content could be adjusted, and optimal electrochemical performance was found in KCoNiPO·HO, which also possessed superior specific capacitance, rate performance, and long-term chemical stability compared with NHCoNiPO·HO because of its unique chemical composition and microstructure. Asymmetric supercapacitor cells based on KCoNiPO·HO and active carbon were assembled, which produce specific capacitance of 34.7 mA h g (227 F g) under current density of 1.5 A g and retain 82% as initial specific capacitance after charging and discharging approximately 5000 times. The assembled asymmetric supercapacitor cells (ASCs) exhibited much higher power and energy density than most previously reported transition metal phosphate ASCs. The KCoNiPO·HO electrodes fabricated in this work are efficient, inexpensive, and composed of naturally abundant materials, rendering them promising for energy storage device applications.