Figure 5 Rate capabilities (a), charge-discharge curves at 2 C (b), and
impedance curves (c) of the LFP electrodes with SCNT-S-1.4%,
SCNT-S-0.7% and the undoped CNTs as conductive additive, fabricated
with NMP as solvent. For LFP, 1 C correspond to 140 mAh
g-1.
3.3.2 Water-based slurry
Compared to NMP, water is a cheaper and safer solvent. Replacing NMP by
water in the electrode fabrications is promising to further reduce the
cost of LIBs. Therefore, we further applied the as-prepared CNTs as
aqueous conductive additives for LFP electrodes, using water rather than
NMP as solvent in the electrode fabrication. As shown in Figure 6a,
obvious CNT agglomerates are observed in the LFP electrode fabricated
with the pristine CNTs aqueous slurry. Similar CNT agglomeration is also
found in the LFP electrode with SCNT-M
(Figure
6b). In contrast, evenly-distributed CNT networks without obvious
agglomeration are found in the LFP electrodes using SCNT-S and SNCNTs
aqueous slurries (Figure 6c and d). It is comprehensible since SNCNTs
and SCNT-S have better hydrophility than SCNT-M and CNTs, thus leading
to better dispersion in aqueous slurries.