SolidEnergy, an MIT spin-out company commercializing solid electrolyte technology, plans to release a 20 Ah EV battery in 2017, which it says will offer more than two times the range of current Li-ion batteries.
The core of SolidEnergy’s technology is a Solid Polymer Ionic Liquid (SPIL) electrolyte, which enables the use of an ultra-thin lithium metal anode. According to the company, this improves cell-level energy density by 50% compared to graphite anodes and 30% compared to silicon-composite anodes.
In 2014, the company announced a prototype 2 Ah pouch cell with a volumetric energy density of more than 1,200 Wh/L. The prototype included a novel electrolyte that combines ionic liquid and liquid polymer, as well as a solid-polymer-coated lithium anode. The solid polymer coating includes dendrite-suppressing additives to prevent dendrite growth.
As SolidEnergy founder Dr. Qichao Hu and his colleagues at MIT noted in a 2011 paper in the Journal of Power Sources: “The use of conventional lithium-ion batteries in high temperature applications (>50° C) is currently inhibited by the high reactivity and volatility of liquid electrolytes. Solvent-free, solid-state polymer electrolytes allow for safe and stable operation of lithium-ion batteries, even at elevated temperatures. Recent advances in polymer synthesis have led to the development of novel materials that exhibit solid-like mechanical behavior while providing the ionic conductivities approaching that of liquid electrolytes.”
SolidEnergy is collaborating with A123 Venture Technologies, a Massachusetts-based technology incubator.