Rational-Designed Hybrid Aerogels for Ultra-Flyweight Electrochemical Energy Storage

Abstract

Hybridising 2D materials into 3D aerogels have attracted considerable interest in ultralight electrochemical energy storage devices. However, to optimise the device structure for more efficient charge storage and transport, a better understanding of the ratio-dependent hybridisation process and interface charge transfer mechanisms are highly required. Here, we perform a comprehensive study to elucidate the fundamental process during the reduced graphene oxide (rGO) and carbon nanotube (CNT) hybridisation, which enabled the fabrication of a rational-designed rGO/CNT hybrid aerogel (GCA) with a record energy storage 2 performance beyond previously reported works. Based on spectroscopy and microscopy analysis, we found the hydrophilic and hydrophobic transition of GO which eliminates the surface-functionalised oxygen-containing moieties, is the origin of the π-π stacking hybridisation between rGO and CNTs. Moreover, we found the different amount of CNTs 'solder' in-between rGO sheets can offer GCA distinct mechanical elasticity, ion diffusion resistance and specific capacitance. As illustrated in the electrochemical impedance spectroscopy (EIS) and charge/discharge analysis, we found GCA 2-2 (rGO:CNT=2:2) display the best gravimetric capacitance of 117 F•g -1 at a discharge current density of 1 A•g -1 , which help us to fabricate an ultra-flyweight supercapacitor with a large energy density of 3.53 Wh•kg -1 at a power density of 283.4 W•kg -1 .

In situ growth CNT@MOFs core—shell structures enabling high specific supercapacitances in neutral aqueous electrolyte

“…Single-walled carbon nanotubes (SWCNTs, purity >95%, external diameter <2 nm, length 0.3−5 μm) purchased from Aladdin Industrial Corporation were used after oxidation treatment by the mixture of H2SO4 and HNO3 (3:1 v/v). Specific methods can refer to our previously published works [38,44].…”

“…Currently, adding electrochemically active materials as additives and composite materials into c-MOF is well acknowledged as an efficient approach. For example, assembling MOFs with high conductive carbon materials such as graphene, CNTs, carbon black, and so on has become an effective strategy for improving energy storage efficiency [21,38,39]. Among these materials, CNTs exhibit high electrical conductivity, large surface area, and excellent cycle life, which enable them to be the most promising conductive composites materials [40].…”

Stable anode enabled by an embossed and punched structure for a high‐rate performance Zn‐ion hybrid capacitor

“…Progress in the field of energy storage systems (ESSs) is highly crucial to addressing the uneven geographical distribution of natural resources such as wind and solar energy. In particular, the ESS consisting of a lithium‐ion battery (LIB) and supercapacitor (SC) used in a complementary relationship is highly favored 1‐5 . The LIBs are primary candidates owing to their high technical maturity and high energy density, whereas the SCs are assisted by high power density, outstanding cycling stability, and high safety 6‐9 .…”

“…In particular, the ESS consisting of a lithium-ion battery (LIB) and supercapacitor (SC) used in a complementary relationship is highly favored. [1][2][3][4][5] The LIBs are primary candidates owing to their high technical maturity and high energy density, whereas the SCs are assisted by high power density, outstanding cycling stability, and high safety. [6][7][8][9] Therefore, the SCs are key to bridging the gap in terms of effective energy leveling and potentially enhancing the performance and stability of the ESS.…”

Hollow Graphene as an Expansion-Inhibiting Electrical Interconnector for Silicon Electrodes in Lithium-Ion Batteries

“…The conductive agent used to secure electrical conducting pathways in a silicon electrode may be also exploited as a buffer phase to suppress dimensional changes upon repeated lithiation and delithiation. However, nano-sized carbon black particles, which conventionally used conductive agents for silicon electrodes, cannot maintain the electrical pathways and the initial microstructures of silicon electrodes against the volume expansion of silicon during cycling. , Although a lot of carbon materials with various nanostructures as conductive agents for lithium-ion batteries have been reported, − to the best of our knowledge, few reports have been published on conductive agents that can act as physical buffers in silicon electrodes. Given that the science and technology of carbon materials has flourished in recent decades, − it is likely that a variety of nanostructured carbon materials can offset mechanical and electrical degradation of silicon electrodes associated with volume changes of silicon during cycling.…”