Nanoengineering Porous Silica for Thermal Management

Abstract

Thermal insulation of solid materials originates from the nanoscale porous architectures to regulate thermal management in energy-critical applications from energy-efficient buildings to heat-sensitive energy devices. Here, we show nanoengineering of porous silica materials to control the architecture transition from mesoporous to nanocage networks. A low thermal conductivity of such a porous silica network is achieved at 0.018 W/(m K) while exhibiting a porosity of 92.05%, specific surface area of 504 m2/g, and pore volume of 2.37 cm3/g after ambient pressure drying. Meanwhile, the crosslinking of the porous silica and ceramic fiber frameworks show a tensile Young’s modulus of 2.8 MPa while maintaining high thermal insulation, which provides an effective thermal runway mitigation strategy for rechargeable lithium-ion batteries. The nanoengineering strategy reported here would shed light on achieving superthermal insulation of nanostructures for energy-critical applications.

Creation of hollow silica-fiberglass soft ceramics for thermal insulation

“…For example, a high porosity with small pore size and the hollow void with thin shell could greatly limit the gas motion, and therefore reduce thermal conductivity. [12,15] Low density (high porosity) reduces the solid-phase thermal conduction. [51] This research aims to control the key properties of G-SiO 2 and L-SiO 2 by varying synthesis parameters.…”

“…[4][5][6] The excellent insulation performance of silica aerogels motivates researches to improve their mechanical properties, [7,8] lower their production cost, [9,10] and develop other nanomaterials with similar properties. [11][12][13][14] Among them, hollow silica micro/nano-sphere show great promise, due to their low thermal conductivity and density, approaching those of silica aerogels. [15][16][17] The voids in hollow silica, similar to those in silica aerogels, interrupt heat transport pathways in both the solid and gas phases.…”

Transparent thermal insulation ceramic aerogel materials for solar thermal conversion

“…The control of the initial pH values is important to obtain a fast hydrolysis rate of TEOS in water inducing homogeneous aggregation with a size dimension smaller than the visible light wavelength. 10,18,19 A lower pH has a faster hydrolysis rate, and thus a smaller domain size could be further frozen during the fast gelation process. The gelation process together with the in situ urea foaming addresses the pore collapsing issue induced by the capillary force.…”

“…Optical transparency and thermal insulation are two important aspects of solar thermal systems and window materials. [9][10][11][12][13] Compared with conventional transparent glass materials, silica aerogels have high-volume nanoporous structures, which bring unique properties such as lightweight (density of 0.01-0.1 g cm À3 ) and ultra-low thermal conductivity (as low as 15 mW m À1 K À1 under ambient conditions). Thus, silica aerogels are ideal for thermal and acoustic insulators.…”

Flexible percolation fibrous thermal insulating composite membranes for thermal management

“…However, silica aerogel shows inherent weak interparticle connections causing poor mechanical performance. The incorporation of fibers could improve porous materials mechanical performance, while the thermal insulating performance could be degraded by the non-uniform microstructures [9][10][11][12][13][14][15] . The occurrence of an accelerated heat transfer through fibers and large void spaces, as part of the solid phase thermal conductivity, dramatically limits the thermal insulating performance of fibrous composite materials and its subsequent structural instability under applied mechanical stress 16,17 .…”