Silicon-Based Anode and Its Full-Cell Performance Test Using a High-Capacity Pouch Cell

Abstract

Despite impressive theoretical capacity, silicon (Si) electrodes suffer from severe pulverization due to enormous volume change. The pulverization leads to low electrical conductivity and reduced diffusivity of lithium ions, resulting in poor rate and cycling ability. In this work, the electrical conductivity of Si electrodes is improved by incorporating carbon nanotubes (CNTs) to enhance the rate and cycling ability. The incorporation of CNTs in the Si electrode is optimized systematically based on the electrode conductivity and cycling performance. Furthermore, the importance of nano-sized conductive carbon in the electrode for achieving an integrated conductive hybrid network across the entire bulk electrode that meets short-range and long-range conduction requirements for the enhancement of electrochemical reactions is explained. The SiCNTs (SiCNTs-30) assessed using coin-type half cells exhibited a higher specific capacity of ∼980 mAh g−1 after 100 cycles at the current density of 0.25 A g−1. Also, the cyclability tests of the SiCNTs-30 anode, paired with the commercial cathode, at the pouch cell level revealed an impressive specific capacity of more than 556 mAh g−1 at 1 C after 500 cycles. Hence, the method shown in this work can pave the way for commercializing SiCNTs hybrid anodes for high-energy and high-power lithium-ion batteries.