Understanding the multiscale dynamic evolution of energy materials under working conditions is essential for clarifying fundamental mechanisms, designing high-performance materials, and advancing dynamic-evolution-based research. In-situ and operando imaging allow the study of material dynamics to progress from indirect mechanistic inference to spatially resolved visual validation, providing direct evidence for investigating where dynamic evolution begins, how it propagates, and how it influences material performance. This review offers a comprehensive, mechanism-focused summary of in-situ and operando imaging applications in revealing the dynamic structural, chemical, and interfacial evolution of materials. It organizes recent advances by representative dynamic evolution behaviors and outlines emerging opportunities to enhance mechanism understanding and materials design through visualized dynamic evidence. Finally, the review discusses future prospects and key challenges in dynamic-evolution-guided materials research, offering guidance for integrating in-situ imaging, working-state identification, and rational materials design.
The urgent need to replace persistent petroleum-based plastics with sustainable alternatives has stimulated growing interest in cellulose, an abundant and renewable biopolymer with considerable potential for advanced materials. However, its intrinsically complex structure fundamentally limits chain mobility, creating a critical barrier to thermal processability and thus restricting its compatibility with conventional thermoplastic manufacturing. Despite extensive efforts to overcome this limitation through diverse physical and chemical strategies, a systematic and critical evaluation of these approaches remains lacking. Herein, we first elucidate the structural origins underlying the non-thermoplastic nature of cellulose, establishing a mechanistic foundation for subsequent processing strategies. We then critically assess state-of-the-art approaches for enhancing thermal processability, including physical treatments (e.g., mechanical disruption and solvent-assisted processing) and chemical modifications (e.g., dynamic covalent chemistry and conventional derivatization), with particular emphasis on their structure–property relationships, advantages, and inherent limitations. The applications of the resulting thermally processible cellulose-based bioplastics are further discussed in the context of performance requirements and practical feasibility. Finally, key challenges associated with current strategies are identified, and future directions are proposed toward the rational design of high-performance, sustainable cellulose thermoplastics. This review provides critical insights into bridging the processability gap of cellulose and aims to accelerate its development as a viable alternative to conventional plastics.
Electrochemical CO2 reduction (CO2R) offers a promising route to convert greenhouse gas emissions into valuable chemicals, but challenges, such as low product selectivity, low current density, insufficient energy efficiency, and material instability, hinder its commercialisation. Addressing these issues requires a deep understanding of the working and degradation mechanisms of electrolysers. In-situ/operando transmission electron microscopy (TEM) offers a powerful method to clarify the structure-performance relationship at the nanoscale. This review critically examines recent advances in the application of in-situ/operando TEM to CO2R, highlighting how these techniques have revealed mechanisms underlying catalyst behaviour and degradation. We discuss current challenges in this research field, identify knowledge gaps, and propose future research directions. This work offers a fundamental understanding and some useful insights for researchers aiming to use advanced TEM to boost the development of CO2 electrocatalysts.
The scaling relations inherent to single-site catalysts impose a fundamental thermodynamic ceiling on their activities for multi-step reactions, which has spurred the exploration of multisite catalysts. While multisite catalysts offer a promising solution, the rational design of cluster-scale heterostructures, an architecture with exceptional potential for multisite synergy, remains hindered by synthetic challenges and incomplete mechanistic understanding. Here, using Pt-Ni catalysts as a model system, we develop a strategy for precise control over multisite configurations, where cluster-scale Pt-NiO heterostructures or PtNi alloy phases can be selectively synthesized via controlling the precursor decomposition kinetics. The Pt-NiO outperforms its PtNi alloy counterpart across four critical alkaline electrocatalytic reactions, including the hydrogen evolution, hydrogen oxidation, oxygen reduction, and methanol oxidation reactions. Mechanistic analyses reveal superior multisite synergy in Pt-NiO, wherein the positively charged Ni sites establish strong Ni-O dipolar interactions that weaken intramolecular O-H bonds, accelerating water dissociation kinetics alongside enhanced hydrogen spillover. Consequently, an anion-exchange membrane water electrolyzer using the cluster-scale Pt-NiO heterostructure as the cathodic electrocatalyst delivers a state-of-the-art current density of 2.0 A cm−2 at 1.74 V with an ultralow Pt loading of 15 μg cm−2. This work establishes a versatile platform for tailoring multisite synergy toward complex reactions in electrochemical energy conversion.
An important challenge for leveraging the fully thermodynamic potential of perovskite solar cells (PSCs) is to enhance carrier selectivity while reducing recombination losses at contact. We address this issue by constructing a majority-dominant contact via a perovskite surface treatment based on 4,4-difluorocyclohexanamine hydriodide. The perovskite surface region undergoes a majority carrier transition from hole concentration of 3.19 × 1019 m−3 to electron concentration of 5.26 × 1019 m−3. Simultaneously, the electron dominance at the electron-selective contact enables super extraction of majority carrier and high resistance to minority carrier, contributing to the reduced interfacial recombination, associated with delocalized trap states and confined ion migrations. The advancements yield a remarkable open-circuit voltage of 1.221 V under a perovskite bandgap of 1.55 eV in single-junction p-i-n PSCs, achieving 95.4% of the Shockley-Queisser limit, and the devices deliver a high efficiency of 26.89% with an extended operating stability. These findings offer significant insights into carrier management at the charge-selective contact for pushing PSCs forward.
