Chemical Bonding Engineering: Insights into Physicochemical Performance Optimization for Energy-Storage/Conversion

Abstract

Chemical bonding is fundamental in determining the physicochemical properties of the materials. Establishing correlations between chemical bonding and these properties may help identify potential materials with unique advantages or guide the composition design for improving the performance of functional materials. However, there is a lack of literature addressing this issue. This Account examines how chemical bonding engineering affects the performance optimization of four widely used or investigated functional materials that are applied in energy-storage/conversion fields, including thermoelectrics, piezoelectrics, lithium-ion batteries (LIBs), and catalysts. The key issues of these materials and correlations between chemical bonding and properties are briefly summarized.

First, electron–phonon coupling hinders thermoelectric performance optimization, representing one of the main issues in the thermoelectric field that needs to be addressed. The role of chemical bonding engineering in electronic and phonon transport is discussed, highlighting how factors such as covalency, electronegativity differences, bond strength, and bond length affect carrier mobility and lattice thermal conductivity. We found that electronic and phonon transport properties can be tuned by modifying the chemical bonding of thermoelectric materials.

Second, the performance of perovskite piezoelectric materials is governed by their phase structure, which is closely associated with ABO₃ lattice distortion. However, clarifying the correlations between perovskite distortion and chemical bonding has long been challenging. The effects of chemical bonding on perovskite distortion and ferroelectric/piezoelectric response are summarized, focusing on lead-free piezoelectric materials. The roles of ionic radii and electronic structures in the ionocovalent bonding between A-/B-site cations and oxygen anions, as well as the stability of perovskite structures, are discussed. These factors are proven to significantly affect the phase structure and piezoelectric response.

Third, during LIB operation, various chemical reactions occur within the electrodes and at the electrode/electrolyte interface, leading to the formation of new reversible or irreversible products. These structural and compositional changes signify a continuous evolution of the chemical bonds within the LIB system. Strategies to enhance the stability of high-capacity electrodes through the development of chemical cross-linker binders are summarized. Additionally, the impact of chemical bonds on the electrochemical stability and lithium-transport capabilities of solid-state electrolytes is also explored. Consequently, deliberately controlling chemical bonds is crucial for optimizing the overall electrochemical performance of LIBs, including parameters such as energy density, cycling lifespan, and fast-charging capabilities.

Fourthly, improving the catalytic activity of catalysts for chemical reactions is the main problem in catalysis. This Account briefly discusses how the bonding parameters of high entropy catalysts can be adjusted by the strain effect and polarity regulation to enhance catalytic activity. The effects of bond parameters and the electronegativity of different elements on the active site and catalytic energy barrier of high entropy catalysts are discussed. We found that adjusting the bonding parameters of high entropy catalysts can influence the adsorption mode during chemical reactions and improve the catalytic activity.

At the end of this Account, several perspectives are proposed, including ongoing challenges and potential directions for future exploration.