Perpustakaan Digital ITB

Silicon (Si) remains one of the most promisinganode materials for next-generation lithium-ion batteries(LIBs). The key challenge for Si anodes is the huge volumechange during lithiation?delithiation cycles that leads toelectrode pulverization and rapid capacity fading. Here, wereport a hierarchical porous Si (hp-Si) with a tailored porousstructure [tunable primary pores (20?200 nm) and secondarynanopores (?3?10 nm)] that can effectively minimize thevolume expansion. An in situ transmission electron micros-copy (TEM) study revealed that the hp-Si material with thesame porosity but larger primary pores can more effectivelyaccommodate lithiation-induced volume expansion, giving riseto a much reduced apparent volume expansion on bothmaterial and electrode levels. Chemomechanical modeling revealed that because of the different relative stiffnesses of thelithiated and unlithiated Si phases, the primary pore size plays a key role in accommodating the volume expansion of lithiated Si.The higher structural stability of the hp-Si materials with larger primary pores also maintains the fast diffusion channels of theconnective pores, giving rise to better power capability and capacity retention upon electrochemical cycling. Ourfindings pointtoward an optimized hp-Si material with minimal volume change during electrochemical cycling for next-generation LIBs