A microgrid-patterned silicon electrode as an electroactive lithium host

Abstract

Lithium (Li) hosts, which can electrochemically accommodate Li in preformed pores of three-dimensional frameworks, have been investigated as an advanced electrode architecture for high-energy-density Li-metal batteries. However, most of the previous studies on Li hosts utilized electrochemically inert materials for their framework constituents, resulting in undesired loss of gravimetric/volumetric energy densities of the resulting batteries. Here, we present an electroactive Li host based on a microgrid-patterned Si electrode (denoted as the MPS host). The MPS host is fabricated using a microscale direct ink writing technique. The lithiophilicity, electronic conductivity, and porous structure of the MPS host are customized to ensure the preferential direction of Li-ion flux and electron conduction into the ordered pore space, while providing the redox capacity. The resulting MPS host enables stepwise sequential Si lithiation/delithiation (from the Si in the microgrid frameworks) and Li plating/stripping (inside the pore space between the microgrids) reactions, verifying its unique behavior as an electroactive Li host. In addition, a full cell assembled with the MPS host and the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode (areal capacity = 3.8 mAh cm(-2)) exhibits high cell energy densities (644 Wh kg(cell)(-1)/1538 Wh L-cell(-1)) and reliable cyclability.