Three-Dimensional Electronic Network Assisted by TiN Conductive Pillars and Chemical Adsorption to Boost the Electrochemical Performance of Red Phosphorus.

The practical application of red phosphorus (P) for sodium-ion batteries (SIBs) is retarded by its poor reversibility and its unstable cycling life derived from its poor conductivity and huge volume expansion. Graphene is considered as an ideal matrix to remedy these weaknesses due to its excellent conductivity and two-dimensional structure. Its π-π restacking causes spatial collapse, however, meaning that graphene cannot effectively buffer volume expansion. Herein, multifunctional TiN is introduced into a P composite to fix this issue. TiN acts as conductive pillars, electron transfer bridges, and a chemical adsorbent of phosphorus in the composite, to prevent the graphene nanoplates from restacking, to bridge gaps between the graphene nanoplates, and to chemically adsorb the P, resulting in the formation of a three-dimensional electronic network and endowing the pulverized P particles with good contact with the conductive matrix to avoid forming insulating "dead P". Consequently, the P composite presents excellent performance for SIBs.