Surface-dominant pseudocapacitive supercapacitors with high specific energy and power for energy storage

The synergistic combination of electric double-layer capacitance (EDLC) and pseudocapacitance is one of the most effective approaches to realize high-performance supercapacitor energy storage. Herein high specific energy and power supercapacitor is realized through the surface-dominant pseudocapacitive charge storage. To demonstrate that, a hybrid 1T-MoS2/Ti3C2Tx porous aerogel is rationally fabricated via bidirectional freeze-casting. The conductive Ti3C2Tx electrically connects the 1T-MoS2 nanosheets, which significantly improves the electron transfer and ion transport, leading to the surface-dominant (up to 86.9%) pseudocapacitive energy storage. As a result, the hybrid aerogel exhibits an outstanding capacitance of 392 F g(-1) at 5 mV s(-1), greatly higher than the conventional 1T-MoS2/Ti3C2Tx film and 1T-MoS2 film. Meanwhile, the Ti3C2Tx-connected 1T-MoS2 architecture achieves high capacitance retention (similar to 38%) at 1000 mV s(-1), which is about 2.9 and 4.7 times higher than that of conventional 1T-MoS2/Ti3C2Tx film and 1T-MoS2 film, respectively. Moreover, the asymmetric supercapacitor delivers both high specific energy (45.3 Wh kg(-1) at 924 W kg(-1)) and specific power (76.4 kW kg(-1) at 18.9 Wh kg(-1)), among the best records of supercapacitors. This work opens new opportunities to develop next-generation high specific energy and power supercapacitors via synergistic effects of EDLC and pseudocapacitance.

Automated summary

The synergistic combination of EDLC and pseudocapacitance has been demonstrated to achieve high-performance supercapacitor energy storage through surface-dominant pseudocapacitive charge storage. A hybrid 1T-MoS2/Ti3C2Tx porous aerogel was fabricated via bidirectional freeze-casting, exhibiting outstanding capacitance and high capacitance retention compared to conventional films. This work opens new opportunities for developing high specific energy and power supercapacitors by leveraging the synergistic effects of EDLC and pseudocapacitance.