Battery metal recycling by flash Joule heating

Abstract

The staggering accumulation of end-of-life lithium-ion batteries (LIBs) and the growing scarcity of battery metal sources have triggered an urgent call for an effective recycling strategy. However, it is challenging to reclaim these metals with both high efficiency and low environmental footprint. We use here a pulsed dc flash Joule heating (FJH) strategy that heats the black mass, the combined anode and cathode, to >2100 kelvin within seconds, leading to ~1000-fold increase in subsequent leaching kinetics. There are high recovery yields of all the battery metals, regardless of their chemistries, using even diluted acids like 0.01 M HCl, thereby lessening the secondary waste stream. The ultrafast high temperature achieves thermal decomposition of the passivated solid electrolyte interphase and valence state reduction of the hard-to-dissolve metal compounds while mitigating diffusional loss of volatile metals. Life cycle analysis versus present recycling methods shows that FJH significantly reduces the environmental footprint of spent LIB processing while turning it into an economically attractive process.

Electric Field Effects in Flash Joule Heating Synthesis

“…Flash Joule heating (FJH), as a method exhibiting high-energy efficiency and an ultrafast heating rate, has recently been used in the synthesis of many materials including graphene, − transition metal chalcogenides, inorganic nanoparticles, , and various other carbide and inorganic compounds. − It has also been widely explored as a method for effective remediation of soil and battery electrodes as well as a method for recycling and upscaling materials. − In contrast to conventional chemical heating methods, which use conductive or radiative heating, Joule heating requires an electric current to flow through the sample itself, which, in turn, directly heats the feedstock. Passing this electric current through the reactants involves imposing an electrical potential difference, typically up to several hundred volts, across a reaction vessel that is several centimeters across, leading to average electric fields on the order of 10 3 –10 4 V/m and a current density of 10 5 –10 7 A/m 2 .…”