Analytical noncovalent electrochemistry for battery engineering

Despite the fact that noncovalent bonding interactions are ubiquitous, it is primarily those interactions, which are amenable to spectroscopic analysis, that have been well investigated and applied in chemical engineering. New principles and techniques for characterizing noncovalent interactions are required to gain insight into their detailed nature and explore their potential applications. Here we introduce the practice of analytical noncovalent electrochemistry for probing such interactions. The strengths of noncovalent interactions can be determined more accurately by electrochemical means than by relying on spectroscopic measurements. Specifically, electrochemical analyses are capable of recording/identifying minor signals, leading to the discovery of an unexpected 2:1 host–guest complex. Moreover, the proposed technique is capable of probing multiple properties and facilitates the design and screening of active complexes as catalysts. We also demonstrate achieving a high energy density of 495 Wh kg−1 in rechargeable batteries. The analytical procedure provides a fresh perspective for supramolecular science and takes noncovalent chemistry closer to practical applications. Quantifying the strength of noncovalent interactions in supramolecular host–guest systems is key to guiding molecular design for a desired application. Now, a quantitative relationship between noncovalent interactions and electrochemistry is established that provides a new dimension for investigations into noncovalent interactions and enables the control of electrochemical properties in battery engineering.