Graphene oxide microrolls as high- content Si carriers boosting Li-ion storage

As attractive anode materials of lithium-ion batteries, both microsized and nanosized silicon particles have been investigated widely, but each has lots of insurmountable problems to restrict their practical applications. In this work, combining the advantages of microsized and nanosized Si particles, we reported a new thought for con-structing micrometer-sized Si/C particles by embedding Si nanoparticles into graphene oxide (GO)-based mirorolls. Differing to the traditional spherical shape, the resulted Si/C microrolls exhibit a unique elastic coil structure with opening ends, facilitating the stress buffer and fast charge diffusion. Besides, in order to maintain the stability of Si nanoparticles in microrolls, we chose the elastic and deformable liquid metal (LM) as the cloth, and sodium alginate (SA) as the thread, successfully tailor a novel tight suit for each Si nanoparticle by a facile self-assembly process. Thanks to the double protection of the conductive-elastic LM-SA coating and the microroll architecture, the resulted Si@LM-SA@GO microroll anode not only has a high Si content of 69 %, a high tap density of 0.62 g cm-3 and a high initial coulombic efficiency of 85.1 %, but also exhibits a superior volumetric capacity of 2506 mAh cm- 3, and a superior cycling performance of 660 mAh cm-3 after 500 cycles at 2 A g- 1. The full cell constructed using a LiNiCoMnO2 cathode can achieve a high reversible capacity of 150 mAh g- 1 at 1C after 250 cycles, delivering a high-energy density of 510 Wh kg- 1.

Automated summary

By embedding silicon nanoparticles into graphene oxide-based mirrorrolls, micrometer-sized Si/C particles with a unique elastic coil structure and double protection were constructed, exhibiting high silicon content, high tap density, and superior cycling performance.