Phytoremediation of Soil Contaminated with Lithium Ion Battery Active Materials—A Proof-of-Concept Study

Andreas Hensel,Uwe Karst,Martin Winter,Sascha Nowak,Patrick Harte,Lukas Schlatt,Jonas Henschel,Julius Buchmann,Fabian Kux,Maximilian Mense,Marcel Diehl

doi:10.3390/recycling5040026

Andreas Hensel, Uwe Karst + Show 9 more

Open Access

https://doi.org/10.3390/recycling5040026

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Abstract

The lithium-ion battery is the most powerful energy storage technology for portable and mobile devices. The enormous demand for lithium-ion batteries is accompanied by an incomplete recycling loop for used lithium-ion batteries and excessive mining of Li and transition metals. The hyperaccumulation of plants represents a low-cost and green technology to reduce environmental pollution of landfills and disused mining regions with low environmental regulations. To examine the capabilities of these approaches, the hyperaccumulation selectivity of Alyssum murale for metals in electrode materials (Ni, Co, Mn, and Li) was evaluated. Plants were cultivated in a conservatory for 46 days whilst soils were contaminated stepwise with dissolved transition metal species via the irrigation water. Up to 3 wt% of the metals was quantified in the dry matter of different plant tissues (leaf, stem, root) by means of inductively coupled plasma-optical emission spectroscopy after 46 days of exposition time. The lateral distribution was monitored by means of micro X-ray fluorescence spectroscopy and laser ablation-inductively coupled plasma-mass spectrometry, revealing different storage behaviors for low and high metal contamination, as well as varying sequestration mechanisms for the four investigated metals. The proof-of-concept regarding the phytoextraction of metals from LiNi0.33Co0.33Mn0.33O2 cathode particles in the soil was demonstrated.

Highlights

Lithium-ion batteries (LIBs) represent the most promising electrical energy storage system for mobile applications due to their superior properties compared to other secondary batteries [1,2,3]
In recent years, layered positive electrode materials based on Ni, Co, and Mn have been increasingly used in LIBs
For Mn, a dieback of A. murale occurred after the addition of 2.50 g Mn

Summary

Introduction

Lithium-ion batteries (LIBs) represent the most promising electrical energy storage system for mobile applications due to their superior properties compared to other secondary batteries [1,2,3].sales figures of LIBs increased drastically in recent years whilst fields of application diverged [4,5] Since and despite several recent innovative approaches, the recycling of used LIBs has fallen short of expectations, and a closed industrial recycling loop has not been established [6,7,8,9].Recycling 2020, 5, 26; doi:10.3390/recycling5040026 www.mdpi.com/journal/recyclinga recycling quota based on weight proportions primarily results in the recovery of cell housing materials. Lithium-ion batteries (LIBs) represent the most promising electrical energy storage system for mobile applications due to their superior properties compared to other secondary batteries [1,2,3]. Sales figures of LIBs increased drastically in recent years whilst fields of application diverged [4,5] Since and despite several recent innovative approaches, the recycling of used LIBs has fallen short of expectations, and a closed industrial recycling loop has not been established [6,7,8,9]. The recycling of Ni-, Co-, Mn-, and Cu-containing electrodes in hydro-metallurgical processes after the already established pyro-metallurgical fractionation is hardly economically feasible to the present state, and the lithium is lost in slag [10,11].

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