<p>Amorphous nanomaterials, which combine short-range order with long-range disorder, provide defect-rich platforms for tailoring electronic structure. This review surveys the controllable synthesis of two-dimensional amorphous metal oxides (2D AMOs)—spanning top-down, topotactic, template-directed, and wet-chemical paradigms—with an emphasis on regulating the amorphous phase while preserving the 2D morphology. We then examine key structural-modification strategies, including phase engineering, single-atom anchoring, conductive hybridization, and defect manipulation. Building on these foundations, their applications in electrochemical energy storage and conversion are discussed to clarify the underlying structure-property-performance relationships. Finally, the remaining bottlenecks and future perspectives are outlined, charting a roadmap toward practical, scalable use.</p>