This study investigates the effects of Cu intercalation into Ti₃C₂Tₓ MXene on its electronic and electrochemical properties. Using X-ray absorption spectroscopy (XAS) and ab initio molecular dynamics (AIMD), the research reveals that Cu²⁺ ions undergo partial reduction upon intercalation, leading to changes in the oxidation states of both Cu and Ti atoms during charging. The pseudocapacitive response of Cu-MXene arises from the redox behavior of both the Cu intercalant and the Ti₃C₂Tₓ host. Despite the high reducing potentials, Cu ions inside the MXene show excellent stability against full reduction. The electronic coupling between Cu ions and Ti₃C₂Tₓ modifies the electrochemical and electronic properties of the latter, providing a framework for the rational design and utilization of transition metal intercalants to tune MXene properties for various electrochemical systems. The study also demonstrates that both Ti and intercalated Cu ions contribute to charge storage, with the Ti oxidation state changing linearly with potential in alkaline electrolytes, indicating a pseudocapacitive charge storage mechanism. The results highlight the potential of Cu intercalation to enhance the electrochemical performance of MXenes, particularly in energy storage applications. The findings suggest that the intercalation of transition metal cations into MXenes can be a promising strategy for tuning their properties for various electrochemical systems.This study investigates the effects of Cu intercalation into Ti₃C₂Tₓ MXene on its electronic and electrochemical properties. Using X-ray absorption spectroscopy (XAS) and ab initio molecular dynamics (AIMD), the research reveals that Cu²⁺ ions undergo partial reduction upon intercalation, leading to changes in the oxidation states of both Cu and Ti atoms during charging. The pseudocapacitive response of Cu-MXene arises from the redox behavior of both the Cu intercalant and the Ti₃C₂Tₓ host. Despite the high reducing potentials, Cu ions inside the MXene show excellent stability against full reduction. The electronic coupling between Cu ions and Ti₃C₂Tₓ modifies the electrochemical and electronic properties of the latter, providing a framework for the rational design and utilization of transition metal intercalants to tune MXene properties for various electrochemical systems. The study also demonstrates that both Ti and intercalated Cu ions contribute to charge storage, with the Ti oxidation state changing linearly with potential in alkaline electrolytes, indicating a pseudocapacitive charge storage mechanism. The results highlight the potential of Cu intercalation to enhance the electrochemical performance of MXenes, particularly in energy storage applications. The findings suggest that the intercalation of transition metal cations into MXenes can be a promising strategy for tuning their properties for various electrochemical systems.