This chapter attempts to provide a brief overview of the various types of electrochemical energy storage (EES) systems explored so far, emphasizing the basic operating principle, history of the development of EES devices from the research, as well as commercial success point of view. The thermodynamic, energy conversion, polarizability, and electrochemical aspects of the devices are touched upon in detail. This chapter also aims to provide a brief insight into the energy storage mechanism, active electrode materials, electrolytes that are presently being used, and the prospects of the prominent conventional EES devices starting from lead-acid batteries, primary batteries, alkali-ion batteries, electrochemical capacitors, fuel cells, etc. An overview of the advantages and disadvantages of each type of EES from electrochemical prospect is outlined in this chapter. © 2023 Elsevier Inc. All rights reserved.