Silicon Composite Anodes: Half and Full Cell Studies

摘要

Carbon-silicon (C-Si) composite anode material was fabricated and used to create electrodes. For C-Si half cells, adding a conductive buffer layer of PVDF/graphene improved adhesion and performance. Cycling with capacity control (1000, 900, 400 mAh/g) improved cycle life over full cycling (0.02 - 1.2V). Thinner electrodes (18μm) with larger particles (1000μm2 surface area) displayed the best cycle life. For NMC half-cells, a recipe of 85% NMC, 10% PVDF, 5% C45 (85/10/5) gave the best adhesion, but worst performance. A 96/2/2 recipe gave poor adhesion, but the best performance due to high active material loading. Calendering to 60% of original thickness improved performance by 100%. For C-Si // NMC full cells, a voltage range of 2.8 - 4.3V gave the best cycle life. Anode pre-lithiation for 1 minute gave ～15% capacity improvement without increasing decay rate, while longer pre-lithiation times were detrimental to performance.