Ever-increasing demand for better batteries has set extraordinarily high standards for electrolyte materials, which are far beyond the realm of a conventional electrolyte design. Superconcentrated (or highly concentrated) solutions are emerging as a new “realistic” class of electrolytes with various unusual functionalities beneficial for advanced battery applications. In this invited contribution, we will introduce our original technical achievements towards (i) versatile salt/solution combination, (ii) ultra high-rate reaction, (iii) high voltage operation over 5 V, iv) corrosion/dissolution prevention, (v) extreme safety, and (vi) advanced high-voltage aqueous energy storage systems, none of which were realized by the conventional electrolytes. Several unique inherent features, as well as the fundamental physicochemical properties, underneath the surprisingly superior battery performance realized by concentrated liquid electrolytes, will be analyzed from the viewpoint of their peculiar solution structure, providing the firm design considerations toward better batteries.