A Study on the Leaching Behavior of Li,  Fe and P from Lithium Iron Phosphate Cathode Powder Using Deep Eutectic Solvents

Hee-Seon Kim; SeongWon Kim; Dae-Weon Kim

doi:10.7844/kirr.2026.35.1.56

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2026 Vol.35, Issue 1 Preview Page Next Page

Research Paper

A Study on the Leaching Behavior of Li, Fe and P from Lithium Iron Phosphate Cathode Powder Using Deep Eutectic Solvents 심층 공융 용매를 사용하여 리튬인산철 양극재 분말로부터 리튬, 철 그리고 인 성분의 침출 거동에 관한 연구

28 February 2026. pp. 56-65

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Abstract

With the increasing global demand for electric vehicles, the end-of-life battery market is rapidly expanding. Consequently, the separation and recovery of valuable resources from spent batteries have attracted increasing interest. Conventional hydrometallurgical recycling processes often cause environmental pollution; hence, environmentally benign processes utilizing green solvents have recently garnered significant attention. In this study, the leaching behaviors of the major elements in lithium iron phosphate cathode powder were investigated using deep eutectic solvents (DESs), which are emerging as eco-friendly alternatives. As comparative studies on various DESs using the same LFP feedstock are limited, five different DESs were evaluated in this work. Based on the experimental results, an optimal DES was selected, and selective leaching of lithium was achieved by optimizing the additives and reaction times. Inductively coupled plasma–optical emission spectrometry analysis indicated a lithium leaching efficiency of approximately 91% for choline chloride–ethylene glycol-based DES combined with K₂S₂O₈ as an oxidizing additive. In addition, phosphorus leaching was suppressed to approximately 3%, and iron was not leached, indicating a high lithium recovery efficiency and superior selectivity. Finally, the feasibility of selective lithium leaching using DESs as environmentally benign solvents was confirmed.

Keywords

LiFePO₄ battery

Deep Eutectic Solvent

DES

Lithium recovery

eco-friendly solvent

전 세계적으로 전기차의 수요가 증가함에 따라 사용 후 배터리 시장 규모 또한 확대되고 있다. 이에 사용 후 배터리로부터 유가 자원을 분리 및 회수하는 연구에 관한 관심이 증가하고 있다. 그중 기존 습식제련 재활용 공정은 환경오염 문제를 야기할 수 있어, 최근 친환경 용매를 이용한 환경 저부담 공정이 주목받고 있다. 이에 본 연구에서는 친환경 용매로 주목받고 있는 심층 공융 용매(Deep Eutectic Solvent, DES)를 활용하여 침출 용매에 따른 LFP 양극재 분말 내 주요 원소들의 침출 거동을 확인하였다. 주요 원소들의 침출 거동 확인 후 리튬 성분의 선택적 침출을 위하여 첨가제 및 반응시간을 공정 변수로 하여 침출 실험을 진행하였다. 공정별 침출액의 ICP-OES 분석을 통해 침출율 및 분리 효율을 비교한 결과 ChCl-EG 기반의 DES를 활용하여 K₂S₂O₈ 산화제를 첨가제로 투입하였을 때의 조건에서 리튬 성분의 침출율은 약 91%, 인 성분은 약 3% 그리고 철 성분은 침출되지 않아 높은 리튬 침출율과 높은 선택도임을 확인할 수 있었다.

키워드

리튬인산철 배터리

심층 공융 용매

DES

리튬 회수

친환경 용매

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Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 35
No :1
Pages :56-65
Received Date : 2025-11-18
Revised Date : 2026-01-07
Accepted Date : 2026-01-14
DOI :https://doi.org/10.7844/kirr.2026.35.1.56

Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

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