Intramolecular Hydrogen Bonds Weaken Interaction Between Solvents and Small Organic Molecules Towards Superior Lithium-Organic Batteries.

Abstract

The strong interaction between organic electrode materials (OEMs) and electrolyte components induces a high solubility tendency of OEMs, thus hindering the practical application of lithium-organic batteries. Herein, we propose an efficient strategy for intramolecular hydrogen bonds (HBs) to redistribute the charge of OEMs to weaken the interaction with electrolyte components, thereby suppressing their dissolution. For the designed 2,2',2''-(2,4,6-trihydroxybenzene-1,3,5-triyl) tris (1H-naphtho[2,3-d]imidazole-4,9-dione) (TPNQ) molecule, the intramolecular HBs (O-H…N and N-H…O) reduce the charge density of active sites and alter the charge distribution on the molecular skeleton. As a result, TPNQ shows significantly reduced solubility in both ether- and ester-based solvents. In-situ measurements and theoretical calculations indicate that the O-H…N dominated HB interaction strengthening during the discharging process, which can continuously suppress dissolution. Therefore, the TPNQ cathode displays high cycling stability (no capacity fading over 100 cycles at 0.1 A g-1; 88.4% capacity retention over 1000 cycles at 1 A g-1), fast Li+-storage kinetics (211 mAh g-1 at 2 A g-1), and surprising low-temperature performances (stability cycles 500 times at -60 °C). Our results offer evidence that the intramolecular HBs strategy is promising in developing robust organic electrode materials for rechargeable batteries.