Scope of Ferrocene in Cathodic Materials of Lithium-Ion Batteries (LIBs): A Review

In modern civilization, the growing energy demand has driven the discovery of new ways to produce energy along with energy storage. Several high-level kinds of research are flourishing on both fronts. The lithium-ion battery (LIB), since its first commercialization from the Sony Corporation, has fulfilled the expectation very well as a portable rechargeable battery. Most electronic devices are now powered by lithium-ion batteries (LIBs), and their application is now further being extended to steer electric vehicles. The biggest concern of the research works associated with LIBs is that it is becoming increasingly difficult to further enhance the energy density of the battery. Cell engineering has played a remarkable role in enhancing the volumetric energy density, but that has also reached its limit. While charging and discharging, lithium-ions (Li-ions) must pass through the active particles coating the electrodes, and therefore, careful control of the size, morphology, and architecture of the cathodic and anodic materials may produce surprising results. Recently, research on ferrocene-based materials such as polymers, nanocomposites, and metal-organic frameworks (MOFs) has gained some momentum because of their potential application as cathodic materials in LIBs owing to their low reactivity towards air, stable voltage range, and fast electrochemical kinetics. It is of note that several polymers with ferrocene either in their backbone or side chain have already been reported as cathodic materials. In the present review, the discussion will be primarily focused on the recent advances in the application and usage of ferrocene-based polymers as cathodic materials of LIBs. Additionally, this review will also summarize the application of some other ferrocene-based materials, e.g. nanocomposites and MOFs, as electrodes/electrolytes of LIBs.