π-π stacking of unsaturated sulfonates on natural graphite enables a green and cost-effective cathode for high-voltage dual-ion batteries

A sustainable and cost-effective energy storage system is the research focus at present and also the development direction of the future. A green and cost-effective cathode material for high-voltage dual-ion batteries (DIBs) is presented in this work through the artificial implantation of unsaturated organic sulfonates on the surface of natural graphite (NG) particles via a low-cost and green synthesis route. It is interesting to discover and validate that pi-pi stacking interactions exist between the pi-bonds of unsaturated sulfonates and graphite layers through both practical experiments and density functional theory simulations. The C0000000000000000000000000000000000000000000000000000111111111111111000000000000000000011111111111111100000000000000000001111111111111110000000000000000000000000000000000000000000000000000C bond-containing propyne sulfonate (PyS) exhibits stronger pi-pi stacking interactions on graphite layers than the C00000000000000000000000000000000111111110000000011111111000000000000000000000000C bond-containing allyl sulfonate and C-C bond-containing propane sulfonate. The PyS layer works as an artificial and highly stable cathode/electrolyte interphase (CEI), which effectively precludes electrolyte decomposition, reduces interfacial resistance and protects the NG cathode from structural degradation. The as-prepared NG@PyS exhibits outstanding cycling performance as the cathode material of DIBs by virtue of the high adhesion capability of PyS on graphite. A green and cost-effective material for dual-ion batteries is obtained by virtue of pi-pi stacking between unsaturated sulfonates and graphite.