高分子量CMC对石墨负极的影响研究

aking graphite as the research object, this paper addresses the bottleneck problem of decreasing electrical conductivity due to high additive amount of traditional low molecular weight CMC in graphite negative electrode application, and systematically centers around graphite negative electrode construction, adopts high molecular weight CMC compounded with SBR, and systematically analyzes the performance of slurry based on the six key physical parameters, namely, laser size, water retention, viscosity, sheet resistance, rebound rate, and compaction density, and systematically analyzes the influence of CMC, SBR, and graphite three factors on the degree of influence on the performance of the slurry. The results show that the pore structure of graphite matrix dominates the formation of conductive network, and high molecular weight CMC can effectively reduce the resistivity of highly expanded silicon-containing graphite anode. In addition, the degree of substitution of CMC and molecular weight show a significant synergistic effect: even with only 1% addition of high substitution CMC (HDS-CMC), it can build a high-strength network with the graphite surface by virtue of the carboxylate (-COO-) group. The three-dimensional framework formed by this network has excellent stability, and the water loss rate remains stable (Δ≤5%) even after the slurry is left to stand for 48 hours. The graphite anode system constructed based on the above mechanism has successfully realized the excellent performance of low resistivity and high stability, which provides a new idea and theoretical basis for the application of high molecular weight CMC in the field of high conductivity electrode binder.