Influence of conductive additives on the electrochemical compatibility of cupper fluoride cathode for FSB

Abstract In this paper, the influence of conductive additives such as single-wall carbon nanotubes (SWCNTs) and acetylene black (AB) on the electrochemical performance of CuF2 based electrodes in fluoride shuttle batteries are studied. CuF2 based-electrodes with different SWCNT and AB concentrations, namely, CuF2/AB4.5/SWCNT1.7 (85.4/4.5/1.7/8.4 in wt%) and CuF2/AB3.8/SWCNT3.8 (73.4/3.8/3.8/19 in wt%), are prepared. Scanning electron and laser microscopy analyses show that the strong van der Waals (VdW) attractions in SWCNTs are reduced when an appropriate ratio between SWCNTs and AB is attained. This aids in the possible reduction of phase separation and aggregation of CuF2-based composite films. It is noticed that the contribution of AB in reducing the aggregation of CuF2 is significantly high as it spreads the entire surface and acts as a bridge between SWCNTs and CuF2. Further, the electrochemical performance test results have revealed significant improvement in the capacity of CuF2 at high C rates when appropriate concentrations of SWCNTs and AB are used. In addition, the recovery of the capacity at all C rates is also improved. The results show that the simultaneous inclusion of both AB and SWCNTs play a critical role to improve the performance of CuF2-based FSBs.