 The study investigates the NAH storage mechanism of hard carbon, HC, under different electrolytes using X-situ electron paramagnetic resonance, EPR, spectra and in-situ Raman spectroscopy, revealing that the initial adsorbed NAH in HC with ether-based electrolytes can be effectively transformed into intercalated NAH, in the plateau region, leading to enhanced electrochemical performance of HC. This article was authored by Gui Yulu, Ji Chang-Wang, Hwaye Min-Yu-Wang, and others.