Extrinsic pseudocapacitance of Ti3C2T MXenes in divalent metal-ion electrolytes after assembly with perylene diimides

Organic materials are an emerging class of charge hosts for the development of sustainable multivalent metal-ion-based electrochemical energy storage devices in the era of post-lithium-ion batteries. In this work, we develop a strategy for spontaneous electrostatic assembly of perylene diimides (PDIs) onto Ti 3 C 2 T x MXene via a solution-processable route. Non-covalent interactions are the key driving force in the formation of such organic-inorganic hybrid electrodes in a binder-free manner. Due to the nanoscale distribution of PDIs across Ti 3 C 2 T x , extrinsic pseudocapacitive characteristics are observed in divalent metal ions, such as Mn 2+ , Zn 2+ , and Ca 2+ , with 3-fold enhancement in charge storage capacity over pristine Ti 3 C 2 T x . This study opens new avenues for the development of MXene-organic hybrid electrode architectures toward the design of high-capacity, high-rate, multivalent metal-ion storage devices.