1992年上海交通大學材料科學與工程學院任教，1995-1997年香港城市大學物理及材料科學系合作研究，2003-2004美國亞利桑那州立大學John M. Cowley高分辨電鏡中心高級訪問學者，現為材料學院教授、博士生導師，目前擔任中國電鏡學會理事以及物理與材料專業委員會委員，中國材料研究學會金屬間化合物與非晶合金分會理事，上海市金屬學會理事、上海市電鏡學會理事、中國金屬學會高級會員。主要研究方向為材料微結構與性質、以及材料模擬與設計，研究的材料包括先進輕金屬、金屬間化合物以及功能陶瓷材料等。先後承擔了10餘項包括國家自然科學基金項目、國家973項目、上海市科委項目以及國際合作項目的研究任務，已發表學術論文100多篇，包括Physical Review B, Applied Physics Letters, Journal of Physics: Condensed Matte, Philosophical Magazine Letters, Acta Materialia, Journal of Materials Research等學術刊物。
代表性論著
1. Xing H., Sun J., Mechanical twinning and omega transition by <111>{112} shear in a metastable beta titanium alloy. Applied physics letters, 93(3), 031908 (2008).
2. Xing H., Sun J., Yao Q., Guo W. Y., Chen R., Origin of substantial plastic deformation in Gum Metals. Applied physics letters, 92(15), 151905 (2008).
3. Yao Q, Xing H and Sun J: Structural stability and elastic property of the L12 ordered Co3(Al,W) precipitate, Applied Physics Letters, 89, 161906 (2006).
4. Yao Q, Sun J, Zhang Y, Jiang B: First-principles studies of ternary site occupancy in the C15 NbCr2 Lave phase, Acta Materialia, 54, 3585 (2006).
5. Zhou O, Yao Q, Sun J, David J Smith: The effect of V addition on structure of ZrCr2 Laves phase: A high-resolution electron microscopy study, Philosophical Magazine Letters, 86, 347 (2006).
6. Sun J, Liu S J, Newman N and Smith D J: Atomic resolution transmission electron microscopy of microstructure of ordered Ba(Cd1/3Ta2/3)O3 perovskite ceramics, Journal of the American Ceramic Society, 89, 1047 (2006).
7. Sun J, Jiang B and Smith D J: EELS near-edge structure in TiCr2 and TiCo2 Laves phase compounds: theoretical and experimental studies, Physical Review B, 69, 214107 (2004).
8. Sun J, Liu S J, Newman N and Smith D J: Ordered domains and boundary structure in Ba(Cd1/3Ta2/3)O3 perovskite dielectrics, Applied Physics Letter, 84, 3918 (2004).
9. Sun J and Jiang B: Ab-initio calculation of phase stability, mechanical properties and electronic structure of the ZrCr2 Laves-phase compounds, Philosophical Magazine, 29, 3133 (2004).
10. Sun J and Smith D J: Electron microscopy characterization of Ba(Cd1/3Ta2/3)O3 microwave dielectrics with boron additive, Journal of Materials Research, 19, 1387 (2004).
