Stability Investigation of Inorganic Li Conductors As Protective Layers for Li-Air Batteries
NASCION-type LiTi2(PO4)3 and perovsikte-La0.50Li0.50TiO3 are known to be inorganic solid electrolytes with adequate conductivity in a range of 10-3 S/cm after required modification. However, Li tends to react with La0.56Li0.33TiO3 due to the incorporation of the released electrons with Ti+4 ions. Simultaneously, Li+ ions will migrate into the vacant sites in the cation sublattice. As a result, La0.50Li0.50TiO3 perovsikte becomes a mixed ionic/electronic conductor after reacting with Li. On the other hand, limited reaction was observed on the Li1+xAlxTi2-x(PO4)3 electrolyte when the metallic Li was used as the anode.
In order to improve the stability of Li1+xAlxTi2-x (PO4)3, a concept of composite electrolyte based on NASCION-type LiTi2(PO4)3 and perovsikte-La0.50Li0.50TiO3 is proposed. With proper mixing and distribution of these two electrolytes, a better stability from the composite electrolyte is expected.
Thus, the objective of this work is (1) to develop a composite electrolyte based on the mixture of Li1+xAlxTi2-x (PO4)3, and La0.50Li0.50TiO3, (2) to analyze the interface reaction between two components of composite cathode, (3) to investigate the electrical conduction/stability of composite as a function of volume fraction, grain size, and thickness, (4) to evaluate the feasibility of using composite electrolyte for Li-Air battery. The stability of composite electrolyte will be determined based on the measurement of the induced electronic conductivity and the open circuit voltage after a Li-air cell is assembled.