Layered double hydroxides (LDHs) have attracted significant attention for their outstanding performance in renewable energy technologies. However, despite their promising electrochemical and catalytic activities, LDHs face challenges owing to their low electrical conductivity and poor chemical stability. Hybridization with nanostructured materials has emerged as a promising solution, as nanoscale coupling with conductive and robust nano species improves both the conductivity and durability of LDHs. The introduction of crystal defects in nanohybrids enhances interfacial interactions between hybridized components, making the combination of defect engineering and hybridization strategies a valuable approach to maximizing the functionality of LDH materials. This review explores the synergistic benefits of combining defect engineering and hybridization approaches in developing energy-functional LDH-based hybrid materials. An in-depth discussion focuses on the evolution of chemical bonding and electronic structures in LDH components. Various examples of defective LDH-based nanohybrids are presented based on different synthesis methods and application fields. In addition, recent advancements in characterization techniques, including in situ spectroscopic analyses, are highlighted. The correlation between chemical features and defect structure in LDH materials is also discussed, along with the impact of different defect types on their energy-related functionalities. Finally, future research perspectives are provided to guide the design and synthesis of economically feasible, energy-functional materials. In summary, combining defect engineering and hybridization improves the performance of LDH-based materials for energy applications. This review emphasizes the potential of designing cost-effective, energy-functional nanohybrids and suggests that future research should refine synthesis methods and explore advanced characterization to enhance their practical use.

Sulfide-based inorganic solid electrolytes are promising materials for high-performance safe solid-state batteries. The high ion conductivity, mechanical characteristics, and good processability of sulfide-based inorganic solid electrolytes are desirable properties for realizing high-performance safe solid-state batteries by replacing conventional liquid electrolytes. However, the low chemical and electrochemical stability of sulfide-based inorganic solid electrolytes hinder the commercialization of sulfide-based safe solid-state batteries. Particularly, the instability of sulfide-based inorganic solid electrolytes is intensified in the cathode, comprising various materials. In this study, carbonate-based ionic conductive polymers are introduced to the cathode to protect cathode materials and suppress the reactivity of sulfide electrolytes. Several instruments, including electrochemical spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy, confirm the chemical and electrochemical stability of the polymer electrolytes in contact with sulfide-based inorganic solid electrolytes. Sulfide-based solid-state cells show stable electrochemical performance over 100 cycles when the ionic conductive polymers were applied to the cathode.