Functional Porous Cubosomes: Synthesis and Applications in Energy Storage and Conversion

Abstract

Nature presents us with numerous complex topological structures, among which ordered bicontinuous structures are widely found in biological systems and exhibit numerous functions, as exemplified by the vibrant wings of butterflies and the robust skeletons of knobby starfish. In recent decades, significant strides have been made in preparing functional materials with bicontinuous porous structures, e.g., cubosomes─spherical colloidal particles, which encompass continuous pores and frameworks arranged in a cubic crystal lattice. These cubosomes exhibit many remarkable advantages due to their unique periodic topological structure. (1) The three-dimensional (3D) interconnected pores facilitate the smooth transport of substances throughout the material, resulting in at least a three times higher utilization ratio of internal active sites compared to that of their unconnected pore or nonporous counterparts. Their complex, tortuous, and periodic porous configuration can enhance energy capture, such as solar/electric energy. (2) The 3D continuous pore channels and frameworks provide “highways” for ion and electron transport, leading to an order-of-magnitude reduction in charge-transfer resistance and an over 3-fold increase in the ion diffusion coefficient compared to those of nonporous analogues, thereby improving the electrochemical kinetics of electrodes. (3) Cubosomes have emerged as unique mechanical metamaterials, exhibiting a remarkable capability to alleviate mechanical stress and strain. (4) Their negative-Gaussian-curvature surfaces facilitate the adsorption/desorption of reaction intermediates, thereby lowering the reaction free energy in catalytic reaction processes. Additionally, this distinctive surface structure can enhance the electric field intensity at material interfaces, significantly promoting ion adsorption. With these advantages, functional cubosomes show potential for application in the field of energy storage and conversion. However, due to the big challenges in their preparation, there have been limited studies on their structure–activity relationships in energy-related applications. Therefore, there has not yet been a review regarding functional cubosomes.

In this Account, we summarize mainly our latest progress in the study of functional cubosomes. First, we introduce the preparation of polymer cubosomes (PCs) through the self-assembly of block copolymers in solution, along with plotting their morphological phase diagram. Then, the Account describes nanocasting approaches in which polymer cubosomes are employed as templates to prepare a variety of functional cubosomes, including polymers, covalent organic frameworks (COFs), metal–organic frameworks (MOFs), metal–phenolic networks, carbons, inorganic metal compounds, and metals. Finally, to elucidate the application prospects of the functional cubosomes, this Account discusses their advantages in different energy storage and conversion applications, highlighting efficient material and energy utilization, fast mass and electron transport, negative-Gaussian-curvature surfaces, and excellent mechanical stability. We anticipate that this Account will demystify functional cubosomes with bicontinuous porous structures and stimulate their broad interest in the fields of materials science, chemistry, and energy, among others.