This review provides a systematic overview of the latest advancements in M₄X₃ MXenes, focusing on their properties and applications in energy storage devices. MXenes are two-dimensional materials with exceptional properties such as high electrical conductivity, good hydrophilicity, and tunable surface properties. They are categorized into different families based on the number of M and X layers in the formula Mₙ₊₁Xₙ. Among these, M₄X₃ MXenes have received relatively less attention and are more challenging to synthesize. However, they exhibit exceptional electronic, magnetic, electrochemical, optical, and mechanical properties, making them highly promising for energy storage applications. Recent studies have shown that M₄X₃ MXenes, such as Ta₄C₃, Nb₄C₃Tₓ, and V₄C₃Tₓ, have excellent electrochemical performance, including high specific capacitance and stable interlayer spacing. These properties make them suitable for use in supercapacitors and other energy storage devices. The synthesis of M₄X₃ MXenes involves various methods, including HF etching, acid/fluoride salt etching, and electrochemical etching. The surface termination of MXenes plays a crucial role in determining their electrochemical performance, and careful control of synthesis parameters is essential for tailoring their properties. The review also discusses the properties and advantages of MXenes appropriate for supercapacitors, including their electronic conductivity, hydrophilicity, mechanical properties, diversity, and surface chemistry. These properties make MXenes highly attractive for various applications, including sensors, thermal heaters, electromagnetic interference shielding, and energy storage. The review highlights the potential of M₄X₃ MXenes for energy storage applications, particularly in supercapacitors, and emphasizes the need for further research to fully explore their capabilities. The study also discusses the electrochemical performance of various M₄X₃ MXenes, including their capacitance, cycle life, and Coulombic efficiency, and highlights the potential of these materials for high-performance energy storage applications.This review provides a systematic overview of the latest advancements in M₄X₃ MXenes, focusing on their properties and applications in energy storage devices. MXenes are two-dimensional materials with exceptional properties such as high electrical conductivity, good hydrophilicity, and tunable surface properties. They are categorized into different families based on the number of M and X layers in the formula Mₙ₊₁Xₙ. Among these, M₄X₃ MXenes have received relatively less attention and are more challenging to synthesize. However, they exhibit exceptional electronic, magnetic, electrochemical, optical, and mechanical properties, making them highly promising for energy storage applications. Recent studies have shown that M₄X₃ MXenes, such as Ta₄C₃, Nb₄C₃Tₓ, and V₄C₃Tₓ, have excellent electrochemical performance, including high specific capacitance and stable interlayer spacing. These properties make them suitable for use in supercapacitors and other energy storage devices. The synthesis of M₄X₃ MXenes involves various methods, including HF etching, acid/fluoride salt etching, and electrochemical etching. The surface termination of MXenes plays a crucial role in determining their electrochemical performance, and careful control of synthesis parameters is essential for tailoring their properties. The review also discusses the properties and advantages of MXenes appropriate for supercapacitors, including their electronic conductivity, hydrophilicity, mechanical properties, diversity, and surface chemistry. These properties make MXenes highly attractive for various applications, including sensors, thermal heaters, electromagnetic interference shielding, and energy storage. The review highlights the potential of M₄X₃ MXenes for energy storage applications, particularly in supercapacitors, and emphasizes the need for further research to fully explore their capabilities. The study also discusses the electrochemical performance of various M₄X₃ MXenes, including their capacitance, cycle life, and Coulombic efficiency, and highlights the potential of these materials for high-performance energy storage applications.