Green recovery of all-solid-state sodium-ion batteries/lithium-ion batteries by ionic liquids, deep eutectic solvents and low-melting mixture solvents

All-solid-state sodium-ion batteries (ASIBs) have good application prospects due to the high energy density, high safety and long lifetime. The excessive use of ASIBs in the near future will inevitably lead to the generation of spent batteries, contributing to environmental pollution and resource waste. In this work, we utilize three types of green solvents—ionic liquids (ILs), deep eutectic solvents (DESs), and low-melting mixture solvents (LoMMSs)—to recover both the cathode and solid electrolyte from ASIBs, as well as the cathode and electrolyte from lithium-ion batteries (LIBs). Results show that the leaching efficiency of Na from the cathode and solid electrolyte of ASIBs by LoMMSs could respectively reach as high as 92.8% and 96.7% at a mild temperature of 80 °C, which is higher than that in ILs and DESs. The highest metal leaching efficiency from ASIBs is similar to that from LIBs. Both LoMMSs and leachate are non-flammable when exposed to a high-temperature torch. In addition, 70 anti-solvents are screened to recover metal from the leachate at room temperature, with acetone yielding the highest precipitation efficiency of 92.0%.

Keywords: Green solvents; Rechargeable batteries; Solid waste; Green chemistry; Physical properties; Anti-solvents.