Viable post-electrode-engineering for the complete integrity of large-volume-change lithium-ion battery anodes

Abstract

The major factor that shortens the cycle life of large-storage-capacity anodes for lithium-ion batteries is the large volume change during cycling, which cause uncontrolled structural dilapidation and the degradation of electrical contact. To overcome this challenge, herein, a robust MgGaZnO (MGZO)-templated Si/reduced graphene oxide (rGO)-web hybrid composite is designed by a broadly applicable and versatile post-electrode-engineering (PEE) process for the first time. Notably, the rGO web accommodates the Si nanoparticles (NPs) during cycling, thereby deriving an rGO-matrix-embedded Si bulk in situ; this electrochemically derived-naturally formed phenomenon is reported for the first time in this Si anode system via PEE. The inner rGO matrix effectively accommodates the volume change owing to its mechanical elasticity and forms continuous electrical interconnects. The outer robust MGZO layer prevents side reactions with the electrolyte, sustaining the structural integrity of the electrode. The dual functioning of this hybrid electrode leads to a significant improvement in the stability via synergistic inner–outer structural treatments. Consequently, a highly stable structure that steadily retains a high capacity (1566 mA h g⁻¹ after 500 cycles) along with an excellent coulombic efficiency (91%) is achieved.