CNT ink as an electrode additive for an effective hybrid conductive network in silicon microparticle/graphite anodes

Abstract

Conductive additives are receiving much attention as they can play an important role in the challenging intrinsic properties of Si anode in lithium-ion batteries. Hence, these carbonaceous materials not only facilitate electrical percolating pathways but also secure structural integrity within the electrode. However, the intrinsic properties of conventional conductive materials such as point-to-point contact of carbon spheres and severe entanglement of CNT make it difficult to achieve an efficient conductive network in the electrode. Here, we use well-dispersed CNT ink as an additive for a homogeneous conductive network in silicon microparticle/graphite (SiMP/Gra) electrodes. By using the CNT ink with Super P particles, a unique hybrid conductive network, composed of 0D and 1D carbon materials, was formed in the SiMP/Gra electrode. To find an optimized conductive structure, a series of electrodes with different weight ratios between CNT and Super P was prepared and electrochemically tested. Through the investigation, the 1 wt% of CNT ink addition makes the best electrochemical performance. The superior performance of SiMP/Gra CNT ink 1.0 wt% electrode can be explained by the optimized hybrid conductive network with Super P cluster bridges between CNT strands. Furthermore, the optimal CNT-Super P hybrid network effectively grasps SiMP/Gra particles and connects electrode components, resulting in improved electrical conductivity and structural integrity upon repeated cycles. The described CNT ink additive concept and the hybrid conductive network could be useful suggestions in electrode design, considering conductive structure and electrochemical performance.