Notably, many significant breakthroughs for a new generation of supercapacitors have been reported in recent years, related to theoretical understanding, material synthesis and device designs. Herein, we summarize the state-of-the-art progress toward mechanisms, new materials, and novel device designs for supercapacitors. Firstly, fundamental understanding of the mechanism is mainly focused on the relationship between the structural properties of electrode materials and their electrochemical performances based on some in situ characterization techniques and simulations. Secondly, some emerging electrode materials are discussed, including metal–organic frameworks (MOFs), covalent organic frameworks (COFs), MXenes, metal nitrides, black phosphorus, LaMnO₃, and RbAg₄I₅/graphite. Thirdly, the device innovations for the next generation of supercapacitors are provided successively, mainly emphasizing flow supercapacitors, alternating current (AC) line-filtering supercapacitors, redox electrolyte enhanced supercapacitors, metal ion hybrid supercapacitors, micro-supercapacitors (fiber, plane and three-dimensional) and multifunctional supercapacitors including electrochromic supercapacitors, self-healing supercapacitors, piezoelectric supercapacitors, shape-memory supercapacitors, thermal self-protective supercapacitors, thermal self-charging supercapacitors, and photo self-charging supercapacitors. Finally, the future developments and key technical challenges are highlighted regarding further research in this thriving field.

An innovative anode material of lithium-ion battery, Li ₃ VO ₄ /Ti ₃ C ₂ T x , was synthesized. The overall three-dimensional electronic and ionic transport pathways were formed in anode, which promoted both electron and ion transport during the lithiation and delithiation processes.

MXene represents new kinds of two-dimensional material transition metal carbides and/or carbonitrides, which have attracted much attention in various applications including electrochemical storage devices, catalysts, and polymer composite. Here, we report a facile method to synthesize Ti₃C₂T_x MXene nanosheets and prepare a novel electrically conductive adhesive based on epoxy resin filled with Ti₃C₂T_x MXene nanosheets by solution blending. The structure, morphology, and performance of Ti₃C₂Tx MXene nanosheets and epoxy/Ti₃C₂T_x MXene nanosheets composite were investigated. The results show that Ti₃C₂T_x MXene possesses nanosheet structure. Ti₃C₂T_x MXene nanosheets were homogeneously dispersed in epoxy resin. Electrical conductivity and mechanical properties measurements reveal that the epoxy/Ti₃C₂T_x MXene nanosheet composite exhibited both good electrical conductivity (4.52 × 10⁻⁴ S/m) and favorable mechanical properties (tensile strength of 66.2 MPa and impact strength of 24.2 kJ/m²) when the content of Ti₃C₂T_x MXene nanosheets is 1.2 wt %. Thus, Ti₃C₂T_x MXene is a promising filler for electrically conductive adhesive with high electric conductivity and high mechanical performance.