“…It is evident that the lithium-ion trapping in the host structure would result in an electrode degradation by direct or indirect electrochemical redox in electroactive support electrolytes, giving rise to irreversible electrochemical reactions. [6][7][8][9][10] Generally accepted in situ or ex situ characterization techniques for probing the electrochemical degradation include electrochemical workstation, [11,12] X-ray diffraction, [13,14] optical spectroscopy, [15,16] Raman spectroscopy, [17] X-ray photoelectron spectroscopy, [18] and in situ transmission electron microscopy (TEM). [19,20] It is reported that tungsten trioxide (WO 3 ) shows a wide range of applications in the field of ECDs, [2] batteries, [21] capacitors, [22] photocatalysis, [23] and electrocatalytic environmental treatment, [24] owing to its reversible interfacial chemical and physical properties such as the reversible transformation from semiconductor (WO 3 ) to conductor (lithium tungsten bronze, Li x WO 3 ) in a Li + -based electrolyte.…”