▎ 摘　　要

NOVELTY - A negative electrode pole piece comprises current collector and silicon-graphene coating. The silicon-graphene coating is painted on two sides of current collector, and comprises silicon layer and graphene layer. The silicon layer is in direct contact with the current collector. The silicon-graphene coating has porosity of 27-33%, silicon mass ratio of 83-90% and graphene ratio of 8-12%. USE - The negative electrode pole piece is used for lithium ion battery (claimed). ADVANTAGE - The pole piece has good cycle performance and high battery capacity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) preparation of the negative electrode pole piece comprising uniformly mixing silicon, nano silicon dioxide, conductive agent and binder at mass% ratio of (85-91) (8-10): (0.5-2.5): (0.5-2.5), and dispersing in organic solvent to obtain silicon layer slurry; uniformly mixing graphite particles and conductive agent at mass% ratio of (97.5-99.5): (0.5-2.5) and dispersing in organic solvent to obtain graphene slurry; immersing current collector in silicon layer slurry, taking out and drying; immersing current collector in graphene slurry, taking out and drying; immersing current collector in hydrofluoric acid, taking out and drying ; and compacting; and (2) lithium ion battery comprising positive electrode pole piece, diaphragm, electrolyte and negative electrode piece.