Water-soluble biowaste gum binders for natural graphite anode for lithium-ion batteries

Abstract

Anode materials for lithium-ion batteries (LIBs) are crucial, as lithium insertion takes place in the anode during the charging process. Also, it is rational to replace the conventional polyvinylidene fluoride (PVdF) with a water-soluble binder because the former employs N-Methyl-2-pyrrolidone, which is environmentally harmful. To address the problem, we fabricated natural graphite (NG)-based anodes with water-soluble biowaste (W-SB) binders from the gum of the tree Cochlospermum gossypium and PVdF. Both of the electrodes were fabricated using 10 wt% of binder and were evaluated for their electrochemical performance. The NG-W-SB electrode showed good mechanical properties and maintained structural integrity after cycling, this promoted low charge transfer resistance on the electrode. NG-W-SB-based electrode showed high current peaks in the 1st cycle being an indication of enhanced electrochemical performance, unlike the NG-PVdF electrode which showed slightly low peaks. NG-W-SB maintained a higher stable capacity retention up to 360 cycles, whereas NG-PVdF had a capacity degradation after 200 cycles indicating a low capacity retention until the end of the cycle. Generally, W-SB binders showed highly enhanced cycling retention characteristics, comparable rate capabilities, and lower electrode resistance, which opened a new avenue for adopting biowaste (gum) as a functional water-soluble binder for LIBs applications.