Open Battery Systems

Global battery demand for stationary storage is expected to increase up to more than 2500 GWh in the next 10 years. In this scenario, the redox flow batteries (RFBs) and metal–oxygen (air) batteries (MABs) represent a strategic alternative to LIBs. RFBs and MABs share a unique feature: unlike conventional LIBs and conventional batteries that are made by two solid electrodes, separated by an electrolyte/separator assembly, and that are hermetically sealed, RFBs and MABs can be considered as “open systems.” Besides the specific electrochemical processes that drive RFB and MAB operation and that will be discussed in the next sections, the open architecture of RFBs and MABs provides an inherent advantage vs. the closed batteries in terms of safety. Indeed, dangerous internal pressure and/or temperature rise that accidentally take place in case of battery failure can be mitigated. In the following, the most recent developments of novel open battery architectures are presented, while promises and challenges of these open systems are discussed.