Architecting Sturdy Si/Graphite Composite with Lubricative Graphene Nanoplatelets for High‐Density Electrodes

Abstract Densification of the electrode by calendering is essential for achieving high‐energy density in lithium‐ion batteries. However, Si anode, which is regarded as the most promising high‐energy substituent of graphite, is vulnerable to the crack during calendering process due to its intrinsic brittleness. Herein, a distinct strategy to prevent the crack and pulverization of Si nanolayer‐embedded Graphite (Si/G) composite with graphene nanoplatelets (GNP) is proposed. The thickly coated GNP layer on Si/G by simple mechanofusion process imparts exceptional mechanical strength and lubricative characteristic to the Si/G composite, preventing the crack and pulverization of Si nanolayer against strong external force during calendering process. Accordingly, GNP coated Si/G (GNP‐Si/G) composite demonstrates excellent electrochemical performances including superior cycling stability (15.6% higher capacity retention than P‐Si/G after 300 cycles in the full‐cell) and rate capability under the industrial testing condition including high electrode density (>1.6 g cm −3 ) and high areal capacity (>3.5 mAh cm −2 ). The material design provides a critical insight for practical approach to resolve the fragile properties of Si/G composite during calendering process.