**4. Conclusions**

In summary, the three-dimensional composite aerogels were prepared with one-dimensional POE nanofibers and two-dimensional RGO sheets. The RGO/POE nanofiber proportions were adjusted to improve the sensing performance of the composite aerogels. The results suggest that the proportions show great impact on volume shrinkage during reduction, compression mechanical behavior, sensitivity, and a working pressure range of the composite aerogels. The aerogels with more POE nanofiber content exhibit lower volume retention, larger stress under the same compression strain, lower sensitivity, and a wider working pressure range. Taking the sensitivity and the working pressure range into consideration, the composite aerogel with POE nanofiber/RGO proportion of 3:3 was selected as the optimal sample, which exhibits high sensitivity (ca. 223 kPa−<sup>1</sup> ) and a wide working pressure range (0–17.7 kPa). It also showed excellent operational stability either compressed with different frequencies or reversibly compressed and released for 5000 times.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2073-4360/11/11/1883/s1, Figure S1: The photographs of the uniform POE nanofiber suspension obtained from different observing angles, Table S1: The volume retention of the prepared GO/POE nanofiber aerogels after reduction.

**Author Contributions:** Conceptualization, D.W., G.S. and M.L.; methodology, W.Z.; software, X.D.; validation, H.J., L.Y. and Y.C.; formal analysis, W.Z.; investigation, W.Z. and X.D.; resources, D.W. and G.S.; data curation, X.D.; writing—original draft preparation, W.Z.; writing—review and editing, A.Y.; visualization, M.L.; supervision, D.W. and G.S.; project administration, W.Z.; funding acquisition, D.W., M.L., and Y.C.

**Funding:** We acknowledge funding support from the National Natural Science Foundation of China (Grant No. 51873165, 51873166, 51603155), Science and Technology Innovation Projects of Hubei Province (2017AHB065), and central guidance for local science and technology development projects (2018ZYYD057).

**Conflicts of Interest:** The authors declare no conflict of interest.
