Nanoscale tin-based intermetallic electrodes encapsulated in microporous copper substrate as the negative electrode with a high rate capacity and a long cycleability for lithium-ion batteries

Abstract

The rate capacity and cycleability of a battery electrode are strongly determined by their chemistry and nano/microstructures. This is particularly true in developing next-generation lithium-ion batteries for electric vehicles. In this article, we report synthesis of nanometer tin based negative electrodes encapsulated in microporous copper substrates, which exhibit simultaneously high-rate and long-life performances. This intermetallic compound consists of an amorphous phase rich in Co, located at the boundaries of nanoscale crystalline Sn–Sb grains. The rate capacity retention is ~71.5% while increasing charge rate from 0.15C (698.9mAhg−1) to 25.0C (500mAhg−1 at ~16Ag−1). Such a high rate performance is a result of novel chemistry (Sn50Sb44Co6) and high electrical conductivity of Cu framework. The cycling capacity is 549mAhg−1 at 0.2C (1C=650mAg−1) after 300 cycles, and 493.6mAhg−1 at 0.4C after 600 cycles. The Co-rich amorphous phase, along with the three dimensional porous structure, contributes to mitigating volume expansion/shrinkage during discharge/charge of the electrode. Our results suggest that the ternary Sn–Sb–Co intermetallic compound with the desirable chemistry and structure is a promising candidate as a high-rate and long-life negative electrode for lithium-ion batteries.