Toyota prototype of solid-state battery

At its event last week in Japan during which it outlined its plans for eco-car development, Toyota displayed a prototype of a solid-state Li-ion battery. The laminated cell measured about 10 x 10 cm.

Four sets of positive electrode layers, solid electrolyte layers and negative electrode layers are laminated, and the average voltage of the cell is 14.4V (3.6V x 4). Because Toyota exhibited the cell right after it was charged, it output a voltage of 16.26V (4.065V per layer). The positive electrode, negative electrode and solid electrolyte of the prototyped cell are made by using lithium cobalt dioxide (LiCoO₂), graphite and sulfide, respectively.

... Furthermore, all-solid-state batteries are safer than organic electrolytes, which burn at high temperatures. And because they do not contain a liquid material, their packages can be simple. All-solid-state batteries have a problem that a material is produced in a chemical reaction between the boundary surfaces of positive electrodes and solid electrolyte, increasing resistance. To solve this problem, Toyota reduced the resistance of the boundary surfaces by 99% by coating the surfaces of positive electrode materials with ceramics with help from the National Institute of Materials Science (NIMS).