Energy storage strategies are essential for addressing climate change and storing energy generated from renewable technologies. As a result, developing a highly efficient, affordable, and environmentally acceptable storage system has become a critical task for the scientific community. The introduction of pseudo-capacitors that exhibits higher charge storage capacity without losing their powerful output capability has provided a considerable advancement in the field of electrochemical energy storage (EES) systems. The fast surface redox kinetics provide an edge to pseudo-capacitors over batteries by providing high energy densities with much superior power densities. This chapter starts with clarifying the misconception between batteries and pseudocapacitive behaviors by briefing the basics of pseudo-capacitors in detail as well as their operating principle along with the various types of pseudo-capacitors and their fingerprint study based on different electrochemical phenomena involved. Furthermore, the chapter will conclude by discussing the various capacitance controlling parameters including energy density, power density, and specific capacitance, their connection to each other, and how they can be enhanced using different electrolytes and working materials.