Crystal engineering promoting degradable polyester separator for high-performance and sustainable lithium-ion batteries

Abstract

The growing awareness of the environmental risks associated with spent lithium-ion battery (LIB) disposal underscores the urgent need for sustainable solutions. Commercial polyolefins separators for LIBs cannot naturally degrade at end of life, which is often destroyed by pyrolysis, causing considerable environment issue. Therefore, developing green and sustainable separators for LIBs seems necessary. Herein, a degradable polyester separator (extended-chain-crystal poly(butylene succinate), E-PBS) is successfully developed through crystal engineering for long-life LIBs. Such an E-PBS separator possesses an ionic conductivity of up to 3.19 mS·cm^–1. The assembled LIBs using this E-PBS separator can achieve much superior capacity retention rates after long cycles to those with commercial polyethylene separators. Moreover, the spent E-PBS separator can be dissolved in lye, which allows the cathode and anode to easily, quickly and efficiently separate. A life cycle assessment shows that this E-PBS separator is more environmentally friendly than the polyethylene separator, with can reduce CO₂ and SO₂ emissions by 42.8 % and 38.0 %, respectively. This work clearly demonstrates that the E-PBS separator is a more sustainable option for next-generation sustainable LIBs.