Prussian blue and its derivatives: towards sustainable next-generation energy storage
Portable and stationary rechargeable batteries are within the many energy-related technologies that require fast progress within the urgent need of remediation of global climate. For example, batteries can still represent up to a third of electric vehicles emissions due to their manufacturing process and lack of end-of-life management. Developing fundamentally sustainable battery materials and electrode processing stands as a central strategy for efficient battery recycling. One essential requirement of next-generation battery technologies is the substitution of costly elements like Li and Co by widely (and more evenly) available ones like Na and Fe in the electrode materials. This implies the development of new energy storage materials, as well synthetic methods.
Materials with porous and hollow morphologies are one of the promising approaches in achieving long-term stability in batteries. Such structures can buffer volumetric changes associated with many energy storage mechanisms (like conversion reactions or ion insertion), avoiding effects like aggregation, structure collapse and loss of conductivity which leads to poor electrochemical performance. Prussian blue (PB, KFe[Fe(CN)6]) and its analogues (PBA, AM[M’(CN)6]) are cheap, easy to synthesize, non-toxic, biocompatible, water and air-stable metal complexes. They have an intrinsic porous framework structure that allows ion intercalation with very little or no strain. Their metal centers are electroactive in both organic and aqueous media. Therefore, this class of materials is ideal for battery electrode applications, achieving high stability and capacity without the need for complex synthetic routes. The tunability of PB(A) structure and composition also makes them versatile template materials. Through different derivatization methods, PB derivatives (PBD) can be prepared. Regardless of the relatively simple structure of PB(A), PBDs present an ever-growing number of compositions that encompass metal oxides, sulfides, phosphides, carbides, hybrids (among others), and an array of morphologies from simple cubes to highly complex hollow and porous structures. Such PBD have recently demonstrated state of the art performance in catalysis and energy storage applications.
This talk will give an overview of the current challenges and strategies to achieve high-performance sustainable batteries, with a focus on PB- and PBD-based electrode materials.