Suppression Strategies for Si Anode Volume Expansion in Li-Ion Batteries Based on Structure Design and Modification: A Review

Silicon anodes have received increasing attention due to their exceptionally high theoretical capacity in lithium-ion batteries (LIBs). However, the defect of anode volume expansion caused by solid-electrolyte interphase (SEI) crushing limits the cycle life seriously. To overcome the obstacle, one must understand the mechanism behind anode volume expansion prior to exploring the suppression strategies. In this review, the recent advances in Si-based anode modification and structural design are categorized comprehensively, the scaled-up framework structures are deeply discussed, and the impacts of various composite structures on cycling performance and Coulombic efficiency are emphasized, particularly the synergistic effects of carbon/MXene assembled with silicon. Some reliable strategies for anode volume expansion restriction have been proposed. The porous structure of monocrystalline silicon spheres reconstructed by alloy sintering can restrain volume expansion effectively due to the reshaped uniform internal stress field. The inner-stress offset induced by Si anode expansion and two-dimensional material layer collapse can provide a perfect inhibition effect on SEI fragmentation when monocrystalline silicon spheres are assembled with graphene or MXene. Moreover, how special nanoshape structures provide anode stability after long cycles are summarized. This current review will be beneficial to facilitate the exploration of strategies for suppression of Si-based anode volume expansion and to pave an avenue for extensive application of Si-based LIBs in the future.