Vertical porous 1D/2D hybrid aerogels with highly matched charge storage performance for aqueous asymmetric supercapacitors

Panji Xu ^1,2,3,4 Kunhua Quan ^1,2,3,4 Xiyuan Wei ^1,2,3,4 Yubing Li ^1,2,3,4 Shuaikai Xu ^1,2,3,4*

• ¹ Center on Nanoenergy Research, nanning, China
• ² Guangxi Key Laboratory of Electrochemical Energy Materials, nanning, China
• ³ State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, nanning, China
• ⁴ School of Physics Science and Technology, Guangxi University, nanning, China

Asymmetric supercapacitors (ASCs) have attracted widespread attention because of their high energy density, high power density and long cycle life. Nevertheless, the development of anodes and cathodes with complementary potential windows and synchronous energy storage kinetics represents a pivotal challenge. We propose to construct nanochannel-coupled vertically porous CNF/Ti3CNTx and CNF/rGO hybrid aerogel electrodes via a unidirectional bottom-up cryoprocess. The vertically porous structure will greatly shorten the ion diffusion path and enhance the charge/ion transfer/diffusion kinetics, and the inserted cellulose nanofibers (CNFs) will impede the re-stacking of the nanosheets and enlarge the interlayer nano-channels, thus improving the accessibility of electrolyte ions. Ultimately, all-solid-state ASCs assembled based on nanochannel-coupled vertically porous MXene and graphene aerogel can achieve an excellent energy density of 20.8 Wh kg−1 at 2.3 kW kg−1, a high multiplicity performance, and retains 95.1% of energy density after 10,000 cycles. This work not only demonstrates the great superiority of nanochannel-coupled vertically porous hybrid aerogels, but also provides an effective strategy for designing asymmetric supercapacitor electrodes with matched structural and electrochemical properties.