In a rechargeable battery,the electrolyte transports lithium ions from the negative to the positive electrode during discharging. The path of ionic flow reverses during recharging. The biological liquid electrolytes in commercial lithium-ion batteries are flammable and subject to leakage, making their large-scale application potentially problematic. Solid electrolytes, or in contrast,overcome these challenges, but their ionic conductivity is typically low.
Source: phys.org