Electrochemical reactions of polycrystalline CrSb2 in lithium batteries

Polycrystalline samples of CrSb2 have been obtained by direct synthesis and allowed to react with lithium in electrochemical cells of the type: Li ∣ LiPF6(EC:DEC) ∣ CrSb2. The cathode contained graphite additives to improve the electrical conductivity of the solid during the first steps of discharge. The discharge of the cell under galvanostatic intermittent titration and continuous discharge at C/4 revealed a main process at ca. 0.6 V leading to the simultaneous destruction of the CrSb2 structure and formation of lithium antimonide, without direct evidence of the topotactic formation of a ternary compound containing lithium. The galvanostatic cycling of the cells reveal capacities above 300 mA h g−1 during the first few cycles and a progressive loss of capacity on prolonged cycling. The performance of the cells shows a significant improvement from the use of pure antimony electrodes, due to the presence of the metallic side product chromium.