Irrigation System-Inspired Open-/Closed-Pore Hybrid Porous Silicon-Carbon Materials for Lithium-Ion Battery Anodes

Porous silicon-carbon (Si-C) nanocomposites exhibit high specific capacity and low electrode strain, positioning them as promising next-generation anode materials for lithium-ion batteries (LIBs). However, nanoscale Si's poor dispersibility and severe interfacial side reactions historically hamper battery performance. Inspired by irrigation systems, this study employs a charge-driven Si dispersion and stepwise assembly strategy to fabricate an open-/closed-pore hybrid porous Si-C composite. Polydimethyl diallyl ammonium chloride (PDDA) is used to functionalize Si nanoparticles, inducing strong electrostatic repulsion for uniform dispersion. Subsequently, the PDDA functional layer on Si nanoparticle surfaces facilitates the stepwise self-assembly of acetic acid and chitosan, resulting in Si nanoparticles encapsulated within closed pores during carbonization. Simultaneously, the PDDA functional layers transform into a graphene coating on the Si nanoparticles. Conversely, regions of homogeneous acetic acid/chitosan, distant from the PDDA-functionalized Si nanoparticles, form an open-pore structure. The dual shielding effect of closed carbon pores and the graphene coating effectively isolates Si from the electrolyte, preventing interfacial side reactions. Open carbon pores enhance electrolyte-active material contact, reducing Li⁺ transport distances. The resulting composite material (PDDA@Si/C) demonstrated excellent cycling stability and superior rate performance as a LIB anode.