Xanthan gum as a water-based binder for P3-Na2/3Ni1/3Mn2/3O2

Abstract

P3-Na2/3Ni1/3Mn2/3O2 (P3-NNM) is a promising cathode material for Na-ion batteries, although large volume expansions during cycling mean that challenges around suitable binders still remain. This study reports the use of xanthan gum as a water-soluble, easy to handle, and sustainable biopolymer binder in conjunction with a P3-Na2/3Ni1/3Mn2/3O2-positive electrode material. The conditions for recovering pristine P3-NNM powders, following water-based processing, are established, and the electrochemical performance of cells prepared using the xanthan gum binder are compared to the more traditional polyvinylidene fluoride. Comparable discharge capacities are observed regardless of the binder choice, at ca. 115 mA h g−1 (77 mAh g−1 after 50 cycles; 0.1 C between 2.0 and 4.2 V). The xanthan gum binder cells also show a similar rate capability and slightly higher capacities at faster c-rates vs. polyvinylidene fluoride, making xanthan gum a viable alternative to the traditional organic binders for water-stable cathode materials.

Binder design strategies for cathode materials in advanced secondary batteries

“…9c, Na 0.67 MnO 2 containing this binder exhibited better electrochemical properties than that using PVDF and SA binders. The structure of the P3 phase was relatively stable both under standard environmental conditions and immersed in water, 173 which is a type of cathode material that is more suitable for using green and water-based binders.…”