Effect of Pyrolysis Temperature on the Leaching Behaviour of Spent Lithium Iron Phosphate Batteries with Sulfuric Acid and Sodium Hydroxide Solution

¹ Department of Metallurgical Engineering, Institut Teknologi Bandung, Indonesia 40132
² Department of Mechanical Engineering, Institut Teknologi Bandung, Indonesia 40132
³ National Center for Sustainable Transporation Technology, Institut Teknologi Bandung, Indonesia 40132
⁴ Mineral Research Institute, Gotion High-Tech Indonesia, Indonesia 12950

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Greenhouse gas emissions from fossil fuel combustion account for approximately 68% of total global emissions, making their reduction essential to mitigating global climate change and achieving Net Zero Emissions by 2050. The transition to electric vehicles has accelerated the demand for lithium-ion batteries, particularly lithium iron phosphate (LFP) types, which are favoured for their reduced dependence to nickel and cobalt. This study explores the recycling of cylindrical spent LFP batteries through a processing involving seawater discharging, pyrolysis at 400–700 °C for 120 minutes, mechanical shredding, particle sieving, and leaching using 2.5 M H₂SO₄ and 5 M NaOH. Samples were characterized using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), and LECO carbon analyser. Pyrolysis at 500 °C produced the highest lithium content in the -45 mesh fraction, reaching 4.11 wt%, and resulted in optimal lithium recovery in the leachate, with 4561.51 mg Li per cell using H₂SO₄ and 1719.32 mg Li per cell using NaOH. Although H₂SO₄ achieved higher lithium extraction, NaOH demonstrated greater selectivity against iron. These findings indicate that 500 °C is an effective pyrolysis temperature for enhancing lithium recovery from spent LFP battery.