High-capacity dilithium hydroquinone cathode material for lithium-ion batteries

Lithiated organic cathode materials show great promise for practical applications in lithium-ion batteries owing to their Li-reservoir characteristics. However, the reported lithiated organic cathode materials still suffer from strict synthesis conditions and low capacity. Here we report a thermal intermolecular rearrangement method without organic solvents to prepare dilithium hydroquinone (Li₂Q), which delivers a high capacity of 323 mAh g^-1 with an average discharge voltage of 2.8 V. The reversible conversion between orthorhombic Li₂Q and monoclinic benzoquinone during charge/discharge processes is revealed by in situ X-ray diffraction. Theoretical calculations show that the unique Li-O channels in Li₂Q are beneficial for Li⁺ ion diffusion. In situ ultraviolet-visible spectra demonstrate that the dissolution issue of Li₂Q electrodes during charge/discharge processes can be handled by separator modification, resulting in enhanced cycling stability. This work sheds light on the synthesis and battery application of high-capacity lithiated organic cathode materials.