Roles of Lithium Aluminum Titanium Phosphate in Lithium Batteries

Lithium aluminum titanium phosphate, abbreviated as LATP, is an important Li+ solid-state electrolyte thanks to its high ionic conductivity and good stability in the ambient atmosphere. Extensive efforts have been devoted to understanding its advanced electrochemical properties. However, the strategy to use it in practical cell is rarely available. In this work, we demonstrate LATP's working behavior via LATP that is coated on a separator facing the cathode and anode, respectively, in both graphite|LiNi0.8Co0.1Mn0.1O2 and Li|LiNi0.8Co0.1Mn0.1O2 cells. With the LATP contact with LiNi0.8Co0.1Mn0.1O2, the cells deliver slightly lower reversible capacity owing to a large Li+ diffusion impedance originated from the space charge layer formed between LATP and cathode and show better durability due to the synergetic Li+ transportation via LATP and organic electrolyte. As for LATP facing graphite, the cells deliver a higher discharge capacity and better cyclic stability. It is ascribed to the buffering and protecting effect of the solid electrolyte interphase (SEI) that reduces the interfacial impedance and precludes the interfacial reaction between LATP and lithiated graphite. When directly in contact with lithium, LATP is decomposed quickly and the cells' performance varies with the recipe of organic electrolytes. This work clearly indicated that LATP could improve the cells' performance when appropriate technologies are utilized to address the associated challenges.