Double-walled carbon nanotubes, a performing additive to enhance capacity retention of antimony anode in potassium-ion batteries

The effect of carbon additives on electrode formulation of bulk antimony was investigated in potassium-ion batteries. Several types of carbon including conventional carbon black, graphite and double-walled carbon nanotubes (DWCNT), employed as conductive agents, were found to play a non-negligible role on the electrochemical performance of antimony. While DWCNT alone show no reversible K+ storage compared to the other carbons, the Sb/DWCNT electrode exhibits better capacity retention and rate capability than Sb formulated with usual carbon additives or even with graphite. This can be ascribed to the specific structure of DWCNT acting not only as conductive additive but also as a mechanical reinforcement for the whole electrode, which has to withstand the large volume change of antimony during potassiation/depotassiation cycles.