Effect of binder on electrode processing of LiFePO 4 cathode for
enhancing the performance of Coin-cell And Pouch-cell
Graphite||LiFePO 4 Batteries
Abstract
This study investigates the influence of two types of binders (aqueous
and non-aqueous) on the LiFePO 4 (LFP) electrode
processing and its electrochemical properties. Specifically,
polyvinylidene fluoride (PVdF) and polyacrylic acid (PAA) were dissolved
in NMP (N-methyl-2-pyrrolidone) or the aqueous solvent (H
2O) at varying mass ratios of 5%, 10%, and 15%.
Binder durability and inertness were assessed by immersing prepared LFP
electrodes in an electrolyte comprising 1.0 M LiPF 6 in
EC:DEC:DMC (1:1:1 in vol%). Notably, PVdF/NMP 10% and PAA/H
2O 10%-based electrodes displayed good durability
without peeling phenomena. Electrochemical characteristics were
evaluated through Cycling Voltammetry (CV) and Galvanostatic Cycling
with Potential Limitation (GCPL). The PAA/H 2O
10%-based-LFP electrode exhibited a specific capacity of approximately
148.9 mAh.g-1 with a Coulombic efficiency (CE) of around 97.27%,
surpassing PVdF/NMP 10%. The graphite||PAA/H
2O 10%-based-LFP electrode in a full cell demonstrated
higher capacity and superior retention after 30 cycles. In a pouch cell
(6 cm x 4 cm), utilizing graphite||LFP with PAA/H
2O 10%, a capacity of 25.5 mAh was achieved,
maintaining 93% capacity with a CE of about 99% after 30 cycles at a
rate of 0.1C.