One-Dimensional π-d Conjugated Coordination Polymer Intercalated MXene Compound for High-Performance Supercapacitor Electrode.

MXenes possess the characteristics required for high-performance supercapacitors, such as high metallic conductivity and electrochemical activity, but their full potential remains unrealized owing to their tendency to self-restack when fabricated into an electrode. Designing an MXene interlayer with an effective intercalant has, therefore, become an important criterion to alleviate the restacking issue while also synergistically interact with MXene to further improve its electrochemical activity. This study reports the intercalation of 1D π-d conjugated coordination polymer (Ni-BTA) within the Ti 3 C 2 T x nanosheet for the fabrication of a highly efficient supercapacitor electrode. Ni-BTA, which consists of a nickel center and 1,2,4,5-benzenetetramine (BTA) organic chain, is uniformly intercalated by direct synthesis on the abundant oxygen terminals on the Ti 3 C 2 T x nanosheet surface. The intercalated Ni-BTA acts as an effective charge carrier transportation pathway through its 1D stretched delocalized π-d electrons while participating in pseudocapacitive activity with the Ni centers. As a result, the Ni-BTA/MXene film exhibits excellent rate performance and a gravimetric specific capacitance of 264.4 F g -1 at 5 mV s -1 . This magnitude is retained up to 94.6% after 10 000 cycles. The present study provides insights into the design of MXene interlayers for the fabrication of highly robust and stable supercapacitors.