Bisthiazolyl Quinones: Stabilizing Organic Electrode Materials with Sulfur-Rich Thiazyl Motifs

Organic electrode materials have emerged as attractive alternatives to electrodes in lithium-ion batteries produced from toxic and unsustainably sourced transition metals. However, low-molecular-weight organic compounds still lack the cycling stability and high-rate capability found in transition-metal electrodes. Herein, we report S-rich thiazyl moieties as a new design feature for small-molecule organic electrode materials. Our findings suggest that S-rich thiazyl moieties engender strong intermolecular interactions that contribute to the insolubility and fast charging of low-molecular-weight quinones. This is demonstrated by the contrasting performance of three isomorphic bisthiazolyl quinones in the solid state: the quinone with the strongest intermolecular interactions can be cycled at a high rate of 10 C for 400 cycles with a 94% capacity retention, while those with weak intermolecular interactions suffer from dissolution and low cycling stabilities (<20 cycles). Our study reveals that S-rich thiazyl moieties may be used to design low-molecular-weight organic electrode materials to achieve long cycle life and fast electrode kinetics.