Solid-state lithium-ion batteries replace the liquid electrolyte with a solid material (Solid-state battery). Some designs also eliminate binders and separators. Solid-state designs are designed to not overheat or catch fire, because the solid electrolyte prevents dendrites from creating short circuits. Acceptance of solid state electrolytes has been limited by the poor conductance of such materials.
Research
In 2014, researchers at Sakti3 announced a solid state electrolyte lithium-ion battery that the company claimed doubles energy density for one fifth of the cost. The company has yet to release details on the materials and construction of its device.
In 2014, researchers from University of Kentucky developed a way to prevent overcharging using organic compounds. Transporting electrons between battery electrodes when excessive current is applied to fully charged batteries prevents this. In 2014 Toyota was developing solid state battery systems for automotive use.
In 2015, researchers announced a solid-state battery that replaced the graphite anode with a sheet of lithium-metal foil. The solid electrolyte is a thin layer applied to the lithium-metal foil. The short distance the ions travel through the solid material has little effect on overall electrolyte conductivity. The liquid electrolyte also has additives that prevent dendrites from forming. The developer claimed that its prototype can be recharged 300 times while retaining 80 percent of its original storage capacity and at room temperature.
In 2016, researchers announced a solid-state battery that resolved the high impedance problem by using an ultra-thin layer of aluminum oxide between the lithium electrode and the solid state "garnet" electrolyte.
In March 2017, researchers announced a solid-state battery with glass electrolytes and 3 times the energy density of conventional lithium-ion batteries. An extended life of more than 1,200 cycles was demonstrated. The design also allows the substitution of sodium for lithium minimizing lithium environmental issues.