NaTi2(PO4)3Solid-State Electrolyte Protection Layer on Zn Metal Anode for Superior Long-Life Aqueous Zinc-Ion Batteries

A fast ion conductor, NaTi2(PO4)(3)(NTP), is hydrothermally synthesized as a solid-state electrolyte protection layer on the surface of Zn anodes (NTP@Zn). NTP has fast ionic conductivity compared with other insoluble phosphates, such as TiP2O7(TPO) and Zn-3(PO4)(2)(ZPO), which is demonstrated by the density-functional theory calculation and cyclic voltammetry tests. X-ray photoelectron spectrometer, X-ray powder diffraction, and HRTEM analyses show that the internal transport/mobility of Zn(2+)can be achieved in NTP layer as an ion passable fence. The NTP layer with a thickness of 20-25 mu m not only prevents side reactions and zinc dendrites, but also improves the reversibility of Zn deposition and electrochemical performance. The NTP@Zn/MnO(2)battery represents the best long-life performance among Zn/MnO(2)batteries to date, which successfully retains a considerable capacity of 105 mA h g(-1)with a CE nearly 100% after 10 000 charge/discharge cycles at 10 C (approximate to 1.5 A g(-1)). Each cycle capacity attenuation rate is only 0.004%. This work represents an advanced step toward long-life Zn metal anodes for aqueous zinc-ion batteries.