Iodine-Mediated Redox Strategy for Sustainable Lithium Extraction From Spent LiFePO4 Cathodes

Abstract

With the widespread application of lithium-ion batteries, the recycling of spent batteries, especially those involving LiFePO₄ (LFP) cathodes for their low-cost and high safety, has become an urgent environmental and resource challenge. Traditional recycling methods (hydrometallurgy and pyrometallurgy) struggle to achieve green and efficient recycling. Herein, this study proposes an iodine-mediated electrochemical strategy to utilize a recyclable I₃⁻/I⁻ redox system and efficiently extract Li⁺ from spent LFP through liquid-phase reactions on one side (achieving a 93% leaching rate and recovery as lithium carbonate), while simultaneously producing metallic zinc through electrodeposition, which can be directly used in Zn-air batteries or hydrogen production. Furthermore, the delithiated LFP is upcycled into an oxygen evolution reaction (OER) catalyst, achieving an overpotential of only 250 mV at 10 mA cm⁻², superior to commercial RuO₂ catalysts. Eventually, this system reduces energy consumption by 32% (9.2 MJ kg⁻¹) compared to traditional hydrometallurgical processes, decreases greenhouse gas emissions by 35% compared to traditional pyrometallurgical processes, while achieving a net profit of ≈$0.44 per kg. This work establishes a novel, scalable recycling system, providing a robust sustainable solution for spent LFP cathodes recycling and clean energy storage.