High Li+-conductive perovskite Li3/8Sr7/16Ta3/4Zr1/4O3 electrolyte prepared by hot-pressing for all-solid-state Li-ion batteries

Air-stable Li(3/8)Sr(7/16)Ta(3/4)Z(4/4)O(3) (LSTZ) is a promising solid electrolyte in all-solid-state Li-ion batteries. However, the low density of the LSTZ pellet reduces its total Li+ conductivity. Hot-pressing technology was introduced to improve the density and Li+ conductivity of LSTZ electrolyte; the influence of the sintering temperature and time on the crystal structure, morphology, mechanical and electrochemical properties of the obtained LSTZ was investigated. LSTZ pellet prepared at 1300 degrees C for 1 h by hot-pressing shows fewer pores, better grain contact and higher compressive strength than the pellet prepared by conventional sintering (CS). The density increase of the LSTZ pellet reduces the Li+ transfer resistance in the grain boundary and improves Li+ conductivity to 4.1 x 10(-4) S cm(-1) at 25 degrees C. The all-solid-state Li/LiFePO4 battery with LSTZ electrolyte showed a high coulombic efficiency, a small overpotential, and a long cycle life.