Dynamically modulating the infrared emissivity of materials is of great importance in various applications (e.g., thermal camouflage and radiative cooling). Even though graphene-based materials (such as multilayer graphene, MLG) have shown great potential in active control of emissivity, the device lifetime is rather short, while low-cost large-scale production is difficult to achieve. Herein, graphene aerogels (GAs) with high porosity are prepared by a simple hydrothermal method, and used as electrode in an infrared emissivity modulator with a sandwiched structure. It is demonstrated that the emissivity of GA can be tuned through ion intercalation by electrostatic gating. The modulation depth of GA is comparable to that of MLG, but device lifetime is much longer. This is likely due to the porous structure of GA formed by a continuous three-dimensional MLG network, which makes it easier for ion transport, while allowing effective charge transfer from anions adsorbed on or intercalated into MLG to carbons. Due to a change in surface roughness of GA upon compressing, the emissivity of GA can be further tuned by compressive strain, which provides additional freedom in control of emissivity. The observations offer a promising avenue for the preparation of large-scale emissivity modulators at low cost, which is beneficial for practical applications.

中文翻译：

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通过离子插层调节石墨烯气凝胶的红外发射率

动态调制材料的红外发射率在各种应用（例如热伪装和辐射冷却）中非常重要。尽管基于石墨烯的材料（如多层石墨烯，MLG）在主动控制发射率方面显示出巨大潜力，但器件寿命较短，难以实现低成本大规模生产。在此，具有高孔隙率的石墨烯气凝胶（GAs）通过简单的水热法制备，并用作具有夹层结构的红外发射率调制器中的电极。证明了GA的发射率可以通过静电门控的离子插层来调节。GA的调制深度与MLG相当，但器件寿命要长得多。这可能是由于 GA 的多孔结构由连续的 3 维 MLG 网络形成，这使得离子传输更容易，同时允许有效的电荷从 MLG 上吸附或嵌入 MLG 的阴离子转移到碳。由于压缩时 GA 的表面粗糙度发生变化，GA 的发射率可以通过压缩应变进一步调整，这为控制发射率提供了额外的自由度。这些观察结果为低成本制备大规模发射率调制器提供了一条有希望的途径，这有利于实际应用。GA 的发射率可以通过压缩应变进一步调整，这为控制发射率提供了额外的自由度。这些观察结果为低成本制备大规模发射率调制器提供了一条有希望的途径，这有利于实际应用。GA 的发射率可以通过压缩应变进一步调整，这为控制发射率提供了额外的自由度。这些观察结果为低成本制备大规模发射率调制器提供了一条有希望的途径，这有利于实际应用。