Strategic Pore Architecture for Accommodating Volume Change from High Si Content in Lithium-Ion Battery Anodes

Abstract

To be a thinner and more lightweight lithium-ion battery with high energy density, the next-generation anode with high gravimetric and volumetric capacity is a prerequisite. In this regard, utilizing high silicon (3579 mAh g(-1)) content in the electrode for the anode has been highlighted as a practically relevant approach. However, there still remains a crucial issue related to intrinsic volume expansion (>300%) of silicon upon lithiation, which can directly affect severe electrode swelling as well as accelerate its capacity fading by triggering structural degradation and electrical contact loss between particles. Herein, macropore-exploited design, which can accommodate the volume change of high silicon content within the extended pore of graphite upon repeated cycling, is introduced. Such unique macropore-exploited design leads to much less electrode swelling, by preserving its morphological integrity and contact between particles, than that of the comparative group with different sized pore and silicon distribution. As a result, this anode (914 mAh g(-1)) demonstrates notable gravimetric (220 Wh kg(-1) at 6000 W kg(-1)) and volumetric energy density (623 Wh L-1 upon full lithiation after 100 cycles), exceeding that of a nano-silicon blended graphite anode (127 Wh kg(-1) and 229 Wh L-1) in the full-cell system.