Chapter 9 - Oxides free materials as anodes for zinc-bromine batteries

Abstract

Energy storage systems, energy can store in the method of chemical, thermal, electric, or kinetic is absorbed and kept for a while before releasing it to provide energy or power services. The main utilization of the energy generated from sustainable and renewable energy resources has a great significance as the probable way out for recent global energy and eco-friendly problems. Regrettably, intrinsic intermittency and trouble in guessing natural renewable resource sources, with sunlight, ocean tides, and wind, can, in the lack of effective energy storage systems. EES is a key empowering agent of the smarter grid, and it relies upon coordinating a substantial quantity of renewable energy production, transmission, and distribution. Also, these EES can transform transportation systems where EES devices might supplant the power train systems of current transportation advancements from a chemical fuel-based force train to an electricity-based power train. These EES can connect global and geographical gaps between energy supply and demand when combined with the other energy infrastructure constituents. In this regard, battery-based effective and rapid charge/discharge response are considered major EES, which provides electric energy storage from renewable resources. Its on-demand release must be energy-efficient, safe, consistent, and economical. By the way, redox flow batteries (RFBs) are recognized as an encouraging choice for larger-scale. RFBs are identified to be the most compatible with grid ESS. Further, RFBs have received huge attention in EESs, particularly for larger-scale electricity storage, owing to greater energy efficiency (EE), cost-effectiveness, and lengthier life. In general, RFBs ideally have no activity loss since they mostly depend on the electrolytes’ electrochemical reactions and not between the electrode and electrolyte. Also, one of the foremost benefits of this battery is its 100% depth of charge-discharge, and it can be left in an entirely discharged state deprived of loss, specifying that its rated capacity is its real capacity. Other benefits are decoupled energy and power, as with fuel cells. RFBs are rechargeable batteries that employ two different liquid electrolyte mediums—one with a positive charge and the other with a negative charge—as energy carriers. More importantly, the electrolyte mediums are separated through an ion-selective membrane, permitting selected ions to pass and complete chemical reactions. The distinctive of this method is the total decoupling between power as well as energy ratings. Notably, the power rate is dogged by the membrane’s active surface and management of the hydraulic pump. Also, the energy capability is mostly governed by the number of electrolytes employed and the tanks’ capacity. The employed electrolyte mediums are separately kept in individual tanks and are propelled into the battery when mandatory. The storage capacity of RFBs can be advanced by purely operating larger storage tanks for the electrolytes. Numerous groupings of chemical constituents are probable for the RFBs. Since both the electrolytes, safety issues from these two active materials can be significantly diminished. Dependent on the engaged redox couple, RFB makes numerous forms. Particularly, these RFBs have been recognized for ESSs usages, including all-vanadium and other V-based systems, hydrogen/bromine (Br2), zinc/Br2, all-chromium, all-cobalt, zinc/cerium, sodium/iodine, all-copper, iron/air, zinc/polyiodide, iron/Br2, polythiophene, aqueous-based lithium/Br2, and even an iron/vanadium system functioning on various redox couples. On the other hand, the current high industrial, working, and maintenance costs of certain RFBs decrease their desirability for commercial usages. To overcome these issues, zinc/Br2 RFBs battery (ZBB) have many advantages that make them appropriate for a larger scale and provide a comparatively priced battery. The ZBBs can also be the potential route to provide greater energy density (70Whkg−1). Regardless, ZBBs have revealed favorable prospects for stationary EES applications. The ZBBs is considered as one of the potential technologies for larger-scale EES credited to its high energy density and lower operational costs. Though, it hurts from lower power density, mostly owing to larger internal resistances affected by the lower conductive nature of electrolyte and great polarization in the positive electrode. Further, some common issues still occur that all the ZBBs have met because of the similar plating-stripping process of the zinc couple in the negative half-cell, assisting through charging-discharging of the battery. These disputes contain zinc dendrite and their accumulation, a limited areal capacity, and a comparatively lower working current density.