Solid-State Dendrite Suppressing Glass-Ceramic Electrolyte for Enabling Lithium Metal Anode

Abstract

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 technology. 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.