Lithium-ion batteries (LiBs) revolutionized energy storage and enabled a new age of electronic devices. They are widely used in many electronic devices such as laptops, cell phones, watches, and even vehicles.
Since its inception, LiB research has driven the technologies closer to its theoretical limits. These limits come with increasing safety concerns including the electrochemical breakdown of the liquid electrolyte at higher voltages and thermal runaway. Exothermic reactions during cycling can lead to ignition of the flammable organic liquid electrolyte and structural damage of the battery can lead to a short circuit, also with the potential for fire.
Aside from safety limitations, existing commercial LiBs are currently paired with lower capacity intercalation anodes, such as graphite (372 mAh/g), rather than utilizing an anode such as lithium metal that has an order of magnitude higher specific capacity (3860 mAh/g). A lithium metal anode will increase volumetric energy density due to its high specific capacity as well as increasing specific energy due to its lower density (0.53 g/cm3) when compared to graphite. While such improvements can be hard using a lithium metal anode, the main reasons it has not yet been commercialized are: instability of pure lithium metal with organic liquid electrolytes, causing parasitic reactions that result in a high impedance interface, and low coulombic efficiency. And most importantly, safety issues are associated with lithium metal anode forming dendrites during cycling, leading to unpredictable short circuits.
A glass-ceramic electrolyte separator is the key to the advancement of Solid-State Lithium metal batteries. JES patented glass electrolyte is low cost, suppresses lithium dendrites and is stable in contact with lithium metal and metal oxide cathode materials. It can repeatedly plate and strip lithium ions in a symmetric Lithium/ Glass/ Lithium half-cell, showing no signs of dendritic shorts or significant degradation in performance. JES glass electrolyte is stable up to 6.5V enabling the use of current and future high voltage cathode materials.
With the glass electrolyte separator, JES’s Solid-State Lithium metal batteries are safer, denser, less expensive, and more robust than the Lithium Ion batteries on the market today. The JES batteries have the potential for 2 to 4 times the energy of lithium-ion batteries in the same size and weight package.
The Solid State batteries with the JES separator can also withstand higher and lower voltages than most conventional batteries and are designed for significantly lower self-discharge than conventional Lithium Ion batteries.
Lithium metal anodes have long been sought to be incorporated into lithium-ion batteries (LiB) in order to increase the energy density and consequently lower the cost of LiB technologies. However, Lithium metal is highly reactive and unstable with many known electrolytes. For those electrolytes stable with Lithium, there is also a risk of Lithium dendrite formation during cycling which will lead to an eventual short and catastrophic failure of the battery.
In this work, we’ve developed a patented proprietary ternary glass-ceramic system, Li2CO3−Li3BO3−Li2SO4 (Patent number: US10566611B2), via molten synthesis that is stable with Lithium. This can suppress dendrite growth during cycling. The bulk crystalline system exhibits lower conductivity of 2 × 10−6 s cm−1 at room temperature. Using rapid quenching of the system to achieve a semi-crystalline or glass phase improves the conductivity to a modest 2 × 10−5 s cm−1 at room temperature. This method allows ultra-thin deposition of the solid electrolyte to reduce its area-specific resistance (ASR) contribution to below 30 Ω·cm2. Lithium symmetric half-cell cycling of a glass sheet shows stable, dendrite-free cycling for at least 350 cycles.
These characteristics make this material ideal to use as a solid-state electrolyte (SSE) separator in full cell testing.