To meet these gaps and maintain a balance between electricity production and demand, energy storage systems (ESSs) are considered to be the most practical and efficient solutions. ESSs are designed to convert and store electrical energy from various sales and recovery needs [, , ].
The traditional energy storage devices are always assembled by pressing the components of electrode membranes and electrolyte membranes [ 20, 21 ], which make the electrode and electrolyte prone to slip and cause an increase of interface barriers, mainly because there is no direct connection between the electrode and electrolyte.
By contrast, the concept of multi-functional energy storage systems is gaining momentum towards integrating energy storage with hundreds of new types of home appliances, electric vehicles, smart grids, and demand-side management, which are an effective method as a complete recipe for increasing flexibility, resistance, and endurance.
Energy storage technologies have various applications in daily life including home energy storage, grid balancing, and powering electric vehicles. Some of the main applications are: Pumped storage utilizes two water reservoirs at varying heights for energy storage.
In order to meet practical applications, many energy storage devices are integrated in series and parallel to increase the capacitance efficiency. As shown in Fig. 4 d, when three devices are connected in series, the output voltage of the supercapacitor increases from 0.8 to 2.4 V, and with no significant voltage drop.
The market for cyclable electrochemical energy storage is dominated by lithium-ion batteries (LIBs) 9, which display GED values ≤0.72 MJ kg −1, four orders of magnitude higher than mechanical springs. However, the capability to store high energy densities typically results in safety risks.