Carbon dioxide (CO₂) is a major greenhouse gas and makes a significant contribution to global warming and climate change. Thus CO₂ capture and storage (CCS) have attracted worldwide interest from both fundamental and practical research communities. Alkali-metal-based oxides such as alkali-metal oxides, binary oxides, and hydrotalcite-like compounds are promising adsorbents for CO₂ capture because of their relatively high adsorption capacity, low cost, and wide availability. They can also be applied to the adsorption-enhanced reactions involving CO₂. The microstructures (e.g., surface area, porosity, particle size, and dispersion) of these oxides determine the CO₂ adsorption capacity and multicycle stability. This perspective critically assesses and gives an overview of recent developments in the synthesized method, adsorption mechanism, operational conditions, stability, and regenerability of a variety of oxides. Both pros and cons of these oxides are also discussed. Insights are provided into several effective procedures regarding microstructural control of alkali-metal-based oxides, including preparation optimization, modification, stream hydration, etc.