Morihiro Saito

A series of isomorphous compounds MBP-1 (M: divalent metal cation) containing M ₂ O ₉ units bridged with 1,3,5-benzenetriphosphonate enable not only to change the metal cation but also to tune its metal site vacancy.

Lithium–air batteries (LABs) are a promising technology for high‐energy‐density battery storage. However, their open‐cell structure for oxygen exchange leads to electrolyte evaporation, which limits cycling performance under ambient conditions. Herein, volatile amide‐based electrolytes for LABs using gravimetric analysis are evaluated. The cell weight change during discharge–charge cycles confirms the two‐electron oxygen reduction/evolution reactions while also revealing that electrolyte evaporation correlates with the solvent vapor pressure. This behavior significantly compromises the cycle performance of low‐viscosity amide electrolyte cells. Despite this, rate‐dependent cycling experiments demonstrate the superior cyclability of the low‐viscosity amide electrolyte cells at high current rates (0.8 mA cm⁻² or higher), conditions under which cells with a conventional tetraethylene glycol dimethyl ether (TEG)‐based LAB electrolyte fail. Scanning electron microscopy and X‐ray diffraction analyses show that these cells exhibit improved rechargeability at high‐rate cycles, with discharge product morphology changing to a more easily decomposable form. This electrolyte design strategy marks a significant advancement toward developing high‐power, high‐energy rechargeable LABs.