The electrochemical behaviors of Li2C8H4O6 and its corresponding organic acid C8H6O6 as anodes for Li-ion batteries

• dilithium 2,5-dihydroxyterephthalate (Li2DHTP) was synthesized via a simple wet chemistry methodology.
• Li2DHTP delivers remarkable cycling and rate performance for Li-ion batteries.
• The electrochemical processes of 2,5-dihydroxyterephthalic acid (DHTPA) and its Li-salt Li2DHTP were firstly proposed.

A functional organic small molecule anode material (dilithium 2,5-dihydroxyterephthalate, Li2DHTP) is synthesized via a simple wet chemistry methodology adopting 2,5-dihydroxyterephthalic acid (DHTPA) as the precursor. It delivers a high specific capacity of 165 mAh/g over 100 cycles with the coulombic efficiency of 98% and shows remarkable rate performance. The organic acid DHTPA also demonstrates electrochemical activity toward Li+ storage and releases but with poor cyclic performance. XRD and FT-IR studies suggest that the de −/lithiation process of chemically replaced Li2DHTP is highly reversible. On the contrary, the de −/lithiation process of electrochemically replaced Li2DHTP intermediate product, where the corresponding DHTPA acid experiences an ion exchange process in the first discharge process, shows quite poor reversibility in the following cycles. The results illustrate that either chemical replacement or electrochemical replacement of DHTPA can generate Li2DHTP electrochemical active material. This methodology might be applied to synthesize advanced organic small molecules conjugated carbonyl materials for energy storage.