Aqueous solution discharge of cylindrical lithium-ion cells

James Shaw-Stewart,Anna Alvarez-Reguera,Agata Greszta,James Marco,Maryam Masood,Rob Sommerville,Emma Kendrick

doi:10.1016/j.susmat.2019.e00110

James Shaw-Stewart, Anna Alvarez-Reguera + Show 5 more

Open Access

https://doi.org/10.1016/j.susmat.2019.e00110

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Abstract

The development of mass-market electric vehicles (EVs) using lithium-ion batteries (LIBs) is helping to propel growth in LIB usage, but end-of-life strategies for LIBs are not well developed. An important aspect of waste LIB processing is the stabilisation of such high energy-density devices, and energy discharge is an obvious way to achieve this. Salt-water electrochemical discharge is often mentioned as the initial step in many LIB recycling studies, but the details of the process itself have not often been mentioned. This study presents systematic discharge characteristics of different saline and basic solutions using identical, fully charged LIB cells. A total of 26 different ionic solutes with sodium (Na+), potassium (K+), and ammonium (NH4+) cations have been tested here using a fixed weight percentage concentration. An evaluation of possible reactions has also been carried out here. The results show good discharge for many of the salts, without significant damaging visual corrosion. The halide salts (Cl−, Br−, and I−) show rapid corrosion of the positive terminal, as does sodium thiosulphate (Na2S2O3), and the solution penetrates the cell can. Mildly acidic solutions do not appear to cause significant damage to the cell can. The most alkaline solutions (NaOH and K3PO4) appear to penetrate the cell without any clear visual damage at the terminals. Depending on what is desired by the discharge (i.e. complete cell destruction and stabilisation or potential re-use or materials recovery), discharge of individual Li-ion cells using aqueous solutions holds clear promise for scaled-up and safe industrial processes.

Highlights

Discharge of lithium-ion battery (LIB) cells is vital for stabilisation during lithium-ion batteries (LIBs) disposal in order to prevent explosions, fires, and toxic gas emission
In the recently published text summarising the conclusions of the publicly-funded German LithoRec projects to develop a commercial LIB recycling process [2], there is a whole chapter devoted to safe discharge of LIBs [3]
A single type of cylindrical cell has been analysed in this study, and the limiting factors have been the positive terminal, whose geometry will vary to a certain extent between models, and the gasket, which could be made of different materials, but needs to be insoluble and non-reactive to the electrolyte solution

Summary

Introduction

Discharge of lithium-ion battery (LIB) cells is vital for stabilisation during LIB disposal in order to prevent explosions, fires, and toxic gas emission. When LIBs are accidentally entrained in lead-acid (Pb-acid) battery smelting input streams, fires and explosions have been reported [1] This highlights the risk that high-energy LIBs can pose during waste processing. In the recently published text summarising the conclusions of the publicly-funded German LithoRec projects to develop a commercial LIB recycling process [2], there is a whole chapter devoted to safe discharge of LIBs [3]. This is needed for both safety and functional reasons, and Hauck and Kurrat [3] outline a number of discharge techniques for different scales, most are a set of different solid electronic techniques,

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