PDF Publication Title:
Text from PDF Page: 012
Energies 2022, 15, 7397 12 of 20 Dr. Li et al. proposed the first concept of ZIFB emphasizing its huge energy capacity value [180]. The power densities of such a battery on the other hand are the worst among competing hybrid technologies due to the low current densities, while the poor cyclability finishes the unfavorable combination. Later Lu et al. used the complexing bromine agents and improved the energy density of the ZIFB even further [181]. Other groups also expand this approach in the frame of the zinc-bromine battery concept [169]. Nevertheless, the problem of insufficient coordination between bromine and iodine components leads to the overcomplicated charge strategy for I2 to become fully charged decreasing the specific capacity practically twice vs. the theoretical value of 268 A h L−1 [182]. Quite recently, Dr. Xie et al. made a breakthrough by adopting the porous polyolefin separator and several high conductive electrolytes in a novel ZIFB system for grid-scale energy storage which demonstrated improved cyclability at 1000 cycles and a current density of 80 mA cm2 [183]. Another work by Dr. Zhang et al. demonstrated an all-aqueous Zn–I2 RFB hybrid system that operates in alkaline media and reaches an energy capacity of 330.5 W h L−1. Today this value is one of the highest energy densities among the all- aqueous hybrid flow systems [184]. One should mention its prominent cyclability over 200 h with 100% coulombic and 70% voltaic efficiencies leading to the value of 70% energy efficiency with 200 W h L−1 volumetric energy capacity. Considering the problem of dendrites in the zinc compartment prof. Xie et al. have developed a self-healing ZIFB, that possesses higher energy capacity and power density, as well as prolonged cyclability [185]. Focusing on the accumulation of zinc dendrites he effectively eliminated the electrolytes precipitation with soluble KI and ZnBr2 as the redox reactants, while the system showed stable operation for more than 1000 cycles over 3 months with an energy density of 80 W h L−1. Moreover, later the stack demonstrated 700 W in 300 cycles experimental test [179]. Another approach tries to make zinc ions more stable by introducing the complexation bromine agents that create cheap and ecologically friendly posolyte and negolyte. To overcome the mentioned above coordination inconsistency that leads to the slow kinetics between zinc and bromine ions one can use a special electrolyte additive to obtain the complexation side process. Adopting K3Fe(CN)6 as the positive redox species to pair with the zinc anode with ZnBr2 modified electrolyte, prof. Yang et al. demonstrated neutral Zn/Fe flow batteries with K3Fe(CN)6 additive, that showed prominent efficiencies and cyclability over 2000 cycles. [186]. In general, problems associated with zinc deposition and dissolution, especially in acid media, are summarized by Prof. Arenas et al. in their review work for the four main types of redox flow batteries employing zinc electrodes: zinc-bromine, zinc-cerium, zinc-air and zinc-nickel [187]. 4. Challenges and Perspectives The transition from traditional vanadium-based redox flow batteries to hydrogen- bromine hybrid chemistry has led to a significant increase in power density in flow systems overcoming the first of two fundamental barriers that significantly hinder the development of the direction: insufficient specific power due to small values of exchange currents for heterogeneous redox reactions used in RFB. The second hindering condition of rather low energy density for flow systems was solved via abandoning the use of dissolved halogens in favor of a new family of aqueous multielectron oxidants–solutions of halogen oxoacids. The latter can effectively participate in the electroreduction process via mediated redox autocatalytic reduction (EC” mechanism) in an acidic medium in the presence of a trace amount of molecular bromine. For a wide range of systems (both model—rotating disc electrode, microelectrodes and fully functional membrane electrode assembly, MEA) it is analytically substantiated, numerically confirmed and experimentally proved the possibility of achieving high current densities (of the order of A cm−2) and peak powers (of the order of W cm−2) in an aqueous solution of halogen oxoacid (e.g., lithium or sodium bromate). Moreover, several studies emphasize thatPDF Image | Halogen Hybrid Flow Batteries
PDF Search Title:
Halogen Hybrid Flow BatteriesOriginal File Name Searched:
energies-15-07397-v2.pdfDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Power up your energy storage game with Salgenx Salt Water Battery. With its advanced technology, the flow battery provides reliable, scalable, and sustainable energy storage for utility-scale projects. Upgrade to a Salgenx flow battery today and take control of your energy future.
| CONTACT TEL: 608-238-6001 Email: greg@salgenx.com | RSS | AMP |