Organic Semiconductor Cocrystal for Highly Conductive Lithium Host Electrode

Abstract In this work, a highly conductive organic cocrystal is investigated as an anode material for conducting agent‐free lithium‐ion battery (LIB) electrodes. A unique morphology of semiconducting fullerene (C 60 ) and contorted hexabenzocoronene (cHBC) is developed as a cocrystal that efficiently enhances the electron transfer during discharge and charge processes due to the formation of a well‐defined junction between C 60 and cHBC. In particular, the present study reveals the exact cocrystal phase of orthorhombic Pnnm using grazing incidence X‐ray diffraction characterization and computational methods. The detailed cocrystal structure analysis indicates that the columnar structure of C 60 /cHBC cocrystal facilitates the reliable vacant sites for Li + storage, which ultimately enhances the reversible capacity to 330 mAh g –1 at 0.1 A g –1 with long cyclability of 600 cycles in the absence of a conducting agent. Furthermore, the rate performance of the C 60 /cHBC cocrystal anode is improved compared to that of the graphite anode, indicating that the cocrystal formation between C 60 and cHBC enhances the charge transport at a high current density. It demonstrates that the approach of this study can be a promising strategy for preparing conducting agent‐free organic cocrystal anodes, which also provides a viable design rule for high‐performance LIBs electrodes.