Easy recovery of Li-ion cathode powders by the use of water-processable binders

Abstract

The continuous growth of the lithium battery market calls for strategies that simultaneously target high energy/power system performance, sustainable manufacturing processes, exploitation of green raw materials and easy recycling of batteries. Here we propose the use of pullulan, a water-soluble and biodegradable polymer, as a binder for the production of LIB cathodes based on Li(Ni0.5Mn0.3Co0.2)O2 (NMC532). We aim to contribute to the development of a sustainable LIB value chain, where devices are designed in view of the recovery of critical elements at their end-of-life. In fact, the aqueous manufacturing of the cathodes represents a green, cheap and easy procedure to produce electrodes with reduced environmental impact and recover Li-ion cathode powders from spent LIBs. The cathodes exhibited up to 135 mAh g−1 of composite material and 167 mAh g−1 of NMC, and excellent cycling stability over 500 cycles along with good capacity retention at high C-rates. NMC and carbon black were directly recovered by dissolving the binder through a water-fed aerograph in less than 2 min. Notably, the waste waters used to wash and recover the NMC-carbon powders were biodegradable, which is of great importance to close the “sustainability chain” loop.