3D hierarchical porous graphene aerogel with tunable meso-pores on graphene nanosheets for high-performance energy storage

Abstract

New and novel 3D hierarchical porous graphene aerogels (HPGA) with uniform and tunable meso-pores (e.g., 21 and 53 nm) on graphene nanosheets (GNS) were prepared by a hydrothermal self-assembly process and an in-situ carbothermal reaction. The size and distribution of the meso-pores on the individual GNS were uniform and could be tuned by controlling the sizes of the Co3O4 NPs used in the hydrothermal reaction. This unique architecture of HPGA prevents the stacking of GNS and promises more electrochemically active sites that enhance the electrochemical storage level significantly. HPGA, as a lithium-ion battery anode, exhibited superior electrochemical performance, including a high reversible specific capacity of 1100 mAh/g at a current density of 0.1 A/g, outstanding cycling stability and excellent rate performance. Even at a large current density of 20 A/g, the reversible capacity was retained at 300 mAh/g, which is larger than that of most porous carbon-based anodes reported, suggesting it to be a promising candidate for energy storage. The proposed 3D HPGA is expected to provide an important platform that can promote the development of 3D topological porous systems in a range of energy storage and generation fields.

Reduced Graphene Oxide-NiO/Ni Nanomembranes as Oxygen Evolution Reaction Electrocatalysts

“…8 It is known that the membrane sample has a tightly packed layered structure, 34 in contrast with the 3D porous structure of the RGO foam. 8,[45][46][47][48][49][50] The higher Tafel slopes of the membrane samples, regardless of iron's presence in the samples, might be partly caused by the insufficient surface area of the catalysts in the membrane. In contrast, the relatively high catalytic activity of the foam sample was possibly attributed to the nanoscopic catalyst interfaces in the graphene 3D structure with an enhanced surface area that was ideally suited for electron transfer and ion transport, for which, further study is underway.…”

Critical Insight into the Relentless Progression Toward Graphene and Graphene‐Containing Materials for Lithium‐Ion Battery Anodes

“…Other kinds of graphene also proved their strength upon long term cycling. Indeed, N-doped RGO, [ 95 ] porous RGO aerogel, [ 96 ] N-doped 3D macroporous RGO, [ 97 ] N-doped graphene (synthesized by bottom-up procedure), [ 98 ] N-S-codoped RGO, [ 99 ] N-F-codoped RGO, [ 100 ] N-doped holey RGO foam, [ 101 ] and porous graphene (obtained by a peculiar top-down process) [ 102 ] displayed some of the most promising electrochemical performances among all graphene-based anodes (Table 1 ). Interestingly, it was also proved that multilayer graphene (obtained by liquid-phase exfoliation in 1-ethyl-3-methylimidazolium acetate ionic liquid) could reversibly store lithium ions down to −30 °C, showing noticeable specifi c gravimetric capacity even when directly compared to its graphite analogue.…”

Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation

“…In energy storage applications such as batteries and supercapacitors graphene has been considered as an electrode material due to the possibility to optimize the physical and chemical properties of its sheets to obtain high specific surface area, high crystallinity and electronic conductivity, enhanced interaction with other electrode components and electrolyte. In Li-ion batteries, graphene either single or multilayer is able to uptake large amounts of Li ions, even higher than commercial graphite, between the graphene sheets and therefore can be used as an active anode material by itself [3,[6][7][8][9] or due to its very high electronic conductivity and high aspect ratio (i.e. low percolation threshold ∼1 wt%) can be used in a composite as a conductive additive and reinforcing component (both in anode and cathode materials) [6,7,[10][11][12].…”