Cellulose/graphite/carbon fibres composite electrodes for Li-ion batteries

Cellulose fibres and an easy aqueous filtration process are used as binder and sheet forming technique, respectively, for the elaboration of mixed graphite (GP)-carbon fibres (CF) composite electrodes for Li-ion batteries. The screening of GP and CF mass fraction in the electrodes showed that the presence of two conducting phases has a synergistic effect on the electrode conductivity when GP and CF percolation networks are simultaneously present. A conductivity peak at 950 S m(-1) was attained for GP and CF volume fractions of 13% and 6%, respectively, corresponding to the percolation threshold of each individual phase. Cellulose/CF electrodes display moderate specific capacity of 200 mA h g(-1) and a good specific capacity retention at high current rate, whereas cellulose GP electrodes demonstrate high specific capacity of about 310 mA h g(-1) and a low specific capacity retention at high current rate which is ascribed to the high binder content, i.e. 20%, and low electron conductivity of 100 S m(-1). The use of CF/GP blends as active materials allows obtaining electrodes with high electron conductivity and specific capacity retention with CF:GP weight ratios ranging between 1:1 and 1:2. (C) 2013 Elsevier Ltd. All rights reserved.