Mechanically Robust, Ultraelastic Hierarchical Foam with Tunable Properties via 3D Printing

Zhang

et al. 2019

Adv Funct Materials

106

3D printing graphene aerogel with periodic microlattices has great prospects for various practical applications due to their low density, large surface area, high porosity, excellent electrical conductivity, good elasticity, and designed lattice structures. However, the low specific capacitance limits their development in energy storage fields due to the stacking of graphene. Therefore, constructing a graphene‐based 2D materials hybridization aerogel that consists of the pseduocapacitive substance and graphene material is necessary for enhancing electrochemical performance. Herein, 3D printing periodic graphene‐based composite hybrid aerogel microlattices (HAMs) are reported via 3D printing direct ink writing technology. The rich porous structure, high electrical conductivity, and highly interconnected networks of the HAMs aid electron and ion transport, further enabling excellent capacitive performance for supercapacitors. An asymmetric supercapacitor device is assembled by two different 4‐mm‐thick electrodes, which can yield high gravimetric specific capacitance (Cg) of 149.71 F g−1 at a current density of 0.5 A g−1 and gravimetric energy density (Eg) of 52.64 Wh kg−1, and retains a capacitance retention of 95.5% after 10 000 cycles. This work provides a general strategy for designing the graphene‐based mixed‐dimensional hybrid architectures, which can be utilized in energy storage fields.

Section: Introductionmentioning

confidence: 99%

Direct Ink Writing of Adjustable Electrochemical Energy Storage Device with High Gravimetric Energy Densities

Zhang

et al. 2019

Adv Funct Materials

106

“…Recently, they have been employed as additively manufactured (AM) foams of tailorable compositions and engineering properties. [9][10][11][12][13][14][15] In many applications, moisture outgassing is of concern when siloxane rubber is in contact with or in close proximity to moisture-sensitive components. In addition, moisture outgassing may result in degradation of interfacial polymer structures, lead to material incompatibility in the system, and compromise the mechanical properties of composite materials.…”

Section: Introductionmentioning

confidence: 99%

Moisture outgassing from siloxane elastomers containing surface-treated-silica fillers

et al. 2019

The outgassing kinetics from siloxane elastomers is dominated by moisture desorption from the reinforcing silica filler and can be detrimental in moisture-sensitive applications. In this study, a custom 3D printable siloxane rubber (LL50) was analyzed in three different states: after a high temperature vacuum heat treatment, limited re-exposure to moisture after vacuum heat treatment, and in the as-received condition. The outgassing kinetics were extracted using isoconversional and iterative regression analyses. Moisture release by physisorbed and chemisorbed water from the samples have activation energies in the range of 50 kJ/mol (physisorbed type) to 220 kJ/mol (chemisorbed type). Overall, moisture outgassing from LL50 was 10 times lower than that from traditionally prepared siloxane rubbers. The vastly diminished moisture content in LL50 is attributed to the existence of a finite low level of silanol groups that remain on the fumed silica surface even after hydrophobic treatment.

“…However, it has been a challenge to perform 3D printing of silicone because of the liquid nature of silicone precursor and crosslinking mechanism. Printability or viscous solution printing (VSP) of silicone is thus restricted to direct ink writing (DIW), a newly developed technique based on the packing of extruded liquid filaments . DIW necessitates special silicone precursor formulation to be nonflowable, thixotropic fluids.…”

Section: Introductionmentioning

confidence: 97%

3D Printed Multifunctional, Hyperelastic Silicone Rubber Foam

Chen

Ren

et al. 2019

Adv Funct Materials

Self Cite

145

131

Highly elastic silicone foams, especially those with tunable properties and multifunctionality, are of great interest in numerous fields. However, the liquid nature of silicone precursors and the complicated foaming process hinder the realization of its three-dimensional (3D) printability. Herein, a series of silicone foams with outstanding performance with regards to elasticity, wetting and sensing properties, multifunctionality, and tunability is generated by direct ink writing. Viscoelastic inks are achieved from direct dispersion of sodium chloride in a unique silicone precursor solution. The 3D-architectured silicone rubber exhibits open-celled trimodal porosity, which offers ultraelasticity with hyper compressibility/cycling endurance (near-zero stress/strain loss under 90% compression or 1000 compression cycles), excellent stretchability (210% strain), and superhydrophobicity. The resulting foam is demonstrated to be multifunctional, such that it can work as an oil sorbent with super capacity (1320%) and customizable soft sensor after absorption of carbon nanotubes on the foam surface. The strategy enables tunability of mechanical strength, elasticity, stretchability, and absorbing capacity, while printing different materials together offers property gradients as an extra dimension of tunability. The first 3D printed silicone foam, which serves an important step toward its application expansion, is achieved.