Environmental impact analysis of the synergistic recycling process of waste three-way catalysts and waste LiCoO 2 batteries

Abstract

Waste three-way catalysts (TWCs) and waste LiCoO₂ batteries represent critical environmental challenges due to hazardous components yet contain high-value resources, and their recycling has garnered widespread attention. We propose a novel ‘waste-to-waste’ synergistic recycling where spent LiCoO₂ batteries reconstruct mineral phases of waste TWCs, enabling co-recovery of platinum group metals and Li/Co without traditional oxidants. However, the environmental performance of this process still requires further analysis. A comprehensive life cycle assessment using the CML2001 framework evaluated seven impact categories across three core phases: carbothermal reduction, oxidation calcination and HCl leaching. The process achieves net-negative environmental impact with significant benefits in abiotic depletion potential elements (−0.062 kg Sb eq.), acidification potential (−120 g SO₂ eq.) and eutrophication potential (−1.09 g phosphate eq.). Compared to the individual recycling of lithium-ion batteries, this synergistic recycling process can reduce CO₂ emissions by approximately 75% or more. Oxidation calcination and HCl leaching are the main phases contributing to environmental burdens. Specifically, electricity consumption, the input of HCl and silicate cement are key factors generating environmental load. Therefore, exploring methods to improve heating efficiency in the oxidation calcination and HCl leaching phases, increasing the proportion of renewable energy in power generation, reducing the use of HCl and seeking environmentally friendly alternatives to silicate cement are crucial to mitigating the environmental impact of this process. Overall, the synergistic recycling process proposed in this study is environmentally friendly and aligns with the goals of a circular economy.