Investigation of electrochemical performance on carbon supported tin-selenium bimetallic anodes in lithium-ion batteries

Bimetallic compound, composed of two different metal elements, has emerged as an important class of electrode system. Amorphous carbon materials are widely used in anodes to reduce the internal resistance of electrodes. Therefore, SnSe bimetallic compound uniformly dispersed in acetylene black as a carbon-support has been fabricated for lithium ion batteries by high energy mechanical milling (HEMM) process under argon atmosphere. The SnSe-C composite retains a reversible capacity of 564 mAh g−1 with a coulombic efficiency of 99.8%, at a current rate of 100 mA g−1 after 50 cycles. In the high rate capability test, the SnSe-C composite exhibits the charge capacity of 530 mAh g−1 at 5000 mA g−1 charge rate. Electrochemical impedance spectroscopy (EIS) results indicate that SnSe-C composite shows small increase of surface resistance than that of plain SnSe composite. The enhanced cycle stability of SnSe-C composite can be attributed to the amorphous carbon additive that offers high electrical conductivity as well as a buffer matrix that prevents the volume change during cycling.