Conductive Additive for Si/Mesoporous Carbon Anode for Li-Ion Batteries: Commercial Graphite vs Carbon Black C65

Silicon exhibits the highest theoretical capacity of 4200 mAh g^-1, which is 10 times more than the capacity of graphite. Therefore, Si is a promising candidate for anode in lithium-ion batteries. However, Si has low electrical conductivity (theoretical: 6.7 x 10^-4 S cm^-1). To reach the high performance anode, the proper conductive additives are still needed in order to improve the electrical conductivity of Si-based anode. Here we investigated the effects of conductive nano-graphite and Carbon Black (CB65) on electrochemical performance of silicon-mesoporous carbon composite anode (Si/MC). The material has been synthesized by pyrolysis of polymer aerogel with embedded Si nanoparticles. The electrode was made by 75% active material, 15% conductive additive, and 10% polyacrylic acid (PAA) binder. The electrochemical characterization using impedance spectroscopy, voltammetry, and galvanostatic charge/discharge tests were conducted for both samples. Impedance spectroscopy showed that Si/MC anode with conductive graphite exhibited lower charge-transfer resistance (R_ct ≈ 150 Ω), compared to those with carbon black (R_ct ≈ 380 Ω). The collected results showed that the graphite additive improved significantly the electrochemical performance of Si/MC anode. In addition, the thermal and long cycling tests will be demonstrated.