LiNi0.5Mn1.5O4 from aqueous slurry and chitosan-based binder: when high performance meets sustainability

Abstract

Strategies for simultaneously producing high-performance electrochemical energy storage systems with sustainable processes are in the spotlight. The first obvious approach is using Co-free cathodes; the second one is the substitution of organic solvent with water in electrode production, with the further improvement of using bio-derived binders. With LiNi_0.5Mn_1.5O₄ (LNMO), a Co-free, high-potential cathode material, we prepare electrodes with chitosan-based binders to assess their performance in Li metal cells with the conventional electrolytic medium that does not contain other fluorinated compounds but the salt. Usually, fluoroethylene carbonate is added in high-voltage cells, instead of vinylene carbonate, to improve anode interface stability. In order to make use of Li metal anode for maximizing the specific power and energy of the cell, we introduce tetraethylammonium hexafluorophosphate, an additive to ameliorate dendrite growth. Additionally, the effect of 1,3-dioxolane (DOL) in the electrolytic mixture is evaluated as an additive able to produce a thin protective layer of poly(1,3)-dioxolane on LNMO by in situ polymerization. The electrodes are characterized by standard electrochemical methods, and the electrochemical study is completed with physicochemical tests and postmortem analyses to assess the feasibility of these sustainable electrodes and the effectiveness of the additives for the stability and cycle life of the material.