Irrigation System-Inspired\nOpen-/Closed-Pore Hybrid\nPorous Silicon–Carbon Materials for Lithium-Ion Battery Anodes

Porous silicon–carbon (Si–C) nanocomposites\nexhibit\nhigh specific capacity and low electrode strain, positioning them\nas promising next-generation anode materials for lithium-ion batteries\n(LIBs). However, nanoscale Si’s poor dispersibility and severe\ninterfacial side reactions historically hamper battery performance.\nInspired by irrigation systems, this study employs a charge-driven\nSi dispersion and stepwise assembly strategy to fabricate an open-/closed-pore\nhybrid porous Si–C composite. Polydimethyl diallyl ammonium\nchloride (PDDA) is used to functionalize Si nanoparticles, inducing\nstrong electrostatic repulsion for uniform dispersion. Subsequently,\nthe PDDA functional layer on Si nanoparticle surfaces facilitates\nthe stepwise self-assembly of acetic acid and chitosan, resulting\nin Si nanoparticles encapsulated within closed pores during carbonization.\nSimultaneously, the PDDA functional layers transform into a graphene\ncoating on the Si nanoparticles. Conversely, regions of homogeneous\nacetic acid/chitosan, distant from the PDDA-functionalized Si nanoparticles,\nform an open-pore structure. The dual shielding effect of closed carbon\npores and the graphene coating effectively isolates Si from the electrolyte,\npreventing interfacial side reactions. Open carbon pores enhance electrolyte-active\nmaterial contact, reducing Li<sup>+</sup> transport distances. The\nresulting composite material (PDDA@Si/C) demonstrated excellent cycling\nstability and superior rate performance as a LIB anode.