Electrochemically inert aluminum cations coordinated with tetrahydroxybenzoquinone toward high-energy storage

Organic carbonyl compounds are a kind of promising cathodes in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) in view of their low cost, structural flexibility, and abundant resources. However, their intrinsic high solubility and low electrical conductivity limit their application. Herein, a novel coordination-driven polymer named aluminum-poly(tetrahydroxybenzoquinone) (PTHBQ-Al) has been synthesized through a facile coordination reaction between tetrahydroxybenzoquinone (THBQ) and aluminum chloride (AlCl3). This polymer exhibited a reversible capacity of 141 mAh g–1 at 100 mA g–1 after 500 cycles in LIBs. Particularly in SIBs, it delivered a reversible capacity of 104 mAh g–1 under the same conditions in ester-based electrolytes. The Coulombic efficiency reached up to 100% in both LIBs and SIBs. In all-organic Li/Na-ion batteries of PTPAn/PTHBQ-Al, reversible charge/discharge capacities of 49/45 and 41/40 mAh g–1 were obtained after 100 cycles at 50 mA g–1, respectively. To classify the reaction mechanism, ex situ FT-IR was further performed. Synchrotron X-ray tomography was used as a nondestructive investigation method to reveal the capacity decay caused by dead lithium/sodium deposition in the anode side, which prevented the transfer of Li+ and Na+ ions and increased the internal battery resistance.