Liquid Metal Remedies Silicon Microparticulates Toward Highly Stable and Superior Volumetric Lithium Storage

Abstract

AbstractA silicon microparticulate material (SiMP) used as the anode for lithium‐ion batteries promises higher volumetric capacity and less interfacial reactions than its costly nanoparticulate counterpart. However, what mostly hinders its practical use is its expansion and pulverization during cycling that induces electrical disconnection and electrode polarization. A liquid metal (LM) is proposed as a remedy for these problems that acts as an adaptive conducting continuum to cure both short‐ and long‐range electrical disconnection. LM encapsulated in a carbon layer constructs a local electrical “ocean” adaptively connecting pulverized Si “islands” upon cycling. Furthermore, carbon nanofibers grown on the LM provide long‐range conducting bridges between the microparticulates, which allow the production of thick electrodes that can be used with SiMPs. With the increased tap densities (4.15 and 1.75 g cm−3 respectively for the composite and the electrode), these thick electrodes give highly stable and superior volumetric lithium storage. These results pave the way for practical compact lithium batteries with SiMPs that have a high‐volumetric energy density.