Toyota prototypes 4-layer solid-state battery

Solid-state batteries have the potential to offer more power output and higher energy storage density than a typical lithium-ion battery. In addition, the reactive liquid electrolyte found in conventional li-ion batteries is thought to lead to cell instability and effect the life span of the battery. Solid-state technology could provide automakers with a battery that not only packs significantly more punch, but also has longevity unmatched by today's liquid electrolyte-based li-ion batteries. Unfortunately, solid-state battery technology is in its infancy and years of additional development lie ahead.
Recently, in Japan, Toyota unveiled a prototype battery that uses a ceramic coating on the positive electrode materials to overcome a problem that has plagued solid-state batteries: material produced in the chemical reaction between the boundary surfaces of positive electrodes and solid electrolyte increases cell resistance. Overcoming this hurdle moves solid-state batteries one step closer to production.

Tech On attended the unveiling in Japan and described the makeup of Toyota's prototype battery like this:

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). The laminated cell measures about 10 centimeters square. Toyota exhibited the cell right after it was charged and 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.

Toyota also confirmed that the prototyped battery can be safely used at temperatures above 212 Fahrenheit, a level that would cause the liquid electrolytes in existing li-ion batteries to boil over.

[Source: Tech On]