Abstract
This review comprehensively analyzes and systematizes modern modification methods aimed at improving the capacitance characteristics of two-dimensional MXene materials, primarily Ti₃C₂Tₓ and related compounds, for their use in supercapacitors and hybrid energy storage devices. The high electronic conductivity, layered structure, and chemically active surface of MXene materials make them promising electrode materials for energy storage devices. However, their practical application is characterized by a number of limitations, such as layer re-densification, limited availability of active centers, and reduced structural stability during long-cycle operation. In this review, the main modification strategies affecting the electrochemical properties of MXene materials are considered, including intercalation-based interlayer spacing control, functionalization of surface terminal groups, composite formation with carbon nanomaterials and transition metal oxides, heteroatom doping, morphological engineering, and various post-processing methods. The impact of these approaches on the ionic and electronic conductivity, pseudocondensation fraction, and cyclic stability of electrode materials is comparatively evaluated. Based on the literature data, a generalized analysis is carried out on the specific capacitance and long-term cyclic stability indicators, and practical recommendations and future research directions for optimizing MXene-based electrodes are formulated.