An Overview on the Development of Electrochemical Capacitors and Batteries – Part I

Abstract

The Nobel Prize in Chemistry 2019 recognized the importance of Li-ion batteries and the revolution they allowed to happen during the past three decades. They are part of a broader class of electrochemical energy storage devices, which are employed where electrical energy is needed on demand and so, the electrochemical energy is converted into electrical energy as required by the application. This opens a variety of possibilities on the utilization of energy storage devices, beyond the well-known mobile applications, assisting on the decarbonization of energy production and distribution. In this series of reviews in two parts, two main types of energy storage devices will be explored: electrochemical capacitors (part I) and rechargeable batteries (part II). More specifi cally, we will discuss about the materials used in each type of device, their main role in the energy storage process, their advantages and drawbacks and, especially, strategies to improve their performance. In the present part, electrochemical capacitors will be addressed. Their fundamental difference to batteries is explained considering the process at the electrode/electrolyte surface and the impact in performance. Materials used in electrochemical capacitors, including double layer capacitors and pseudocapacitive materials will be reviewed, highlighting the importance of electrolytes. As an important part of these strategies, synthetic routes for the production of nanoparticles will also be approached (part I).

Gel Biopolymer Electrolytes Based on Saline Water and Seaweed to Support the Large‐Scale Production of Sustainable Supercapacitors

“…Thus, we set 1 V as the operating voltage of the device because values below or above À 0.8 and 0.2 V vs. Ag/AgCl, respectively, increased due to undesirable faradaic reactions. [41,42] Typically, hydrogen evolution (HER) and oxygen evolution (OER) reactions occur on the negative and positive electrodes of aqueous supercapacitors, respectively. [41] Our results show good behavior for the device in terms of negative potentials, reaching values near the HER potentials in water.…”

“…Conversely, when the other electrode is negatively polarized, the cations move to the surface to compensate for the negative surface. [42] The formation of this EDL determines the electrode capacitance and creates different regions in the electrolyte as a function of ion concentration. A compact layer (Stern layer) is formed near the electrode surface to store energy, and there are no free charges here [48].…”

Lithium-Ion Capacitors: A Review of Design and Active Materials

“…Figure 1 gives an overview of the power and energy densities of ultracapacitors and LIBs compared to other energy storage technologies. A common target for advanced electrical energy storage systems is to provide high energy as well as high power in a single system [35][36][37][38]. A LIC is a comparatively modern system, intermediate in energy between batteries and supercapacitors, though giving supercapacitor-like power and cyclability properties.…”

Sensitivity Analysis and Optimization of a Liquid Cooling Thermal Management System for Hybrid Fuel Cell Aircraft

“…Among the various possible approaches in electrification is the hybridization of the conventional propulsion system. For this hybridization, fuel cells seem to be a promising solution due to their higher specific energy and energy densities compared to traditional battery sources [1]. However, one drawback with fuel cells is that they typically exhibit efficiencies of around 50% meaning they produce as much heat as they do power.…”