Co‐Crosslinked Water‐Soluble Biopolymers as a Binder for High‐Voltage LiNi0.5Mn1.5O4Graphite Lithium‐Ion Full Cells

摘要

The use of water‐soluble, abundant biopolymers as binders for lithium‐ion positive electrodes is explored because it represents a great step forward towards environmentally benign battery processing. However, to date, most studies that employ, for instance, carboxymethyl cellulose (CMC) as a binder have focused on rather low electrode areal loadings with limited relevance for industrial needs. This study concerns the use of natural guar gum (GG) as a binding agent for cobalt‐free, high‐voltage LiNi Mn O (LNMO), which realizes electrodes with substantially increased areal loadings, low binder content, and greatly enhanced cycling stability. Co‐crosslinking GG through citric acid with CMC allows for an enhanced rate capability and essentially maintains the beneficial impact of using GG as a binder rather than CMC only. Lithium‐ion full cells based on water‐processed LNMO and graphite electrodes provide a remarkably high cycling stability with 80 % capacity retention after 1000 cycles at 1 C.