High energy density is of primary concern for lithium ion batteries (LIBs) and sodium ion batteries (SIBs) in the practical application for consumer electronics and electric vehicles (EVs). Layered structure (Li1.2Mn0.54Co0.13Ni0.13O2, LiNi0.8Co0.1Mn0.1O2 and Na0.67Mn0.54Ni0.13Co0.13O2) and spinel structure (LiNi0.5Mn1.5O4) are prominent cathode materials employed in commercial LIBs and SIBs. However, these materials faced challenges with surface side reaction with electrolyte, dissolution of transition metal (TM) ions, and irreversible surface phase transformation, leading to performance fading and safety hazard. Our group focus on surface modification to address these problems via atomic layer deposition (ALD) and molecular layer deposition (MLD), which is capable of depositing highly conformal and uniform layers with well controlled thickness onto materials. Furthermore, we use synchrotron based X-ray spectroscopy to help understanding detailed mechanism of modification.
Atomic-scale Manipulation of Spinel Lithium Nickel Manganese Surface by Tetrahedrally-coordinated Ti as High Performance Cathode. (2016) submitted.
Y. Zhao, X. Li, D. Xiong, D. Li, S. Lawes and X. Sun, Recent Development and Understanding of Novel Mixed Transition-Metal Oxides as Anodes in Lithium Ion Batteries. Adv. Energy Mater., 6 (2016) 1502175.(Invited review)
K. Kaliyappan, J. Liu, A. Lushington, R. Li and X. Sun, Highly Stable Na3/2(Mn0.54Ni0.13Co0.13)O2 Cathode Modified by Atomic Layer Deposition for Sodium-Ion Batteries. Chem. Sus. Chem 8 (2015) 2537
J. Wang and X. Sun, Olivine LiFePO4: the Remaining Challenges for Future Energy Storage. Energy Environ. Sci. 8 (2015) 1110-1138
B. Xiao, J. Liu, Q. Sun, B. Wang, M. Banis, D. Zhao, Z. Wang, R. Li, X. Cui, T.-K. Sham and X. Sun, Unravelling the role of electrochemically active FePO4 coating by atomic layer deposition for increased high-voltage stability of LiNi0.5Mn1.5O4 cathode material. Adv. Sci. (2015) 1500022 (Highlighted by "MaterialsView China" and "MaterialsView")
X. Li, J. Liu, M. Banis, A. Lushington, R. Li, M. Cai, X. Sun, Atomic Layer Deposition of Solid-State Electrolyte Coated Cathode Materials with Superior High-Voltage Cycling Behavior for Lithium Ion Battery Application. Energy Environ. Sci. 7 (2) (2014) 768-778
J. Wang, J. Yang, Y. Tang, J. Liu, Y. Zhang, G. Liang, M. Gauthier, Y. K. Chen, M. Banis, X. Li, R. Li, J. Wang, T. -K. Sham, X. Sun, Size-dependent Surface Phase Change of Lithium Iron Phosphate during Carbon Coating. Nat. Commun. 5 (2014) 3145 (Highlighted by "Western Media Relations" and "The Londoner Local News")
Y. Hu, X. Sun, Flexible Rechargeable Lithium Ion Batteries: Advances and Challenges in Materials and Process Technologies. J. Mater. Chem. A 2 (2014) 10712-10738 (Invited review)
D. Wang, J. Yang, X. Li, D. Geng, R. Li, M. Cai, T.-K. Sham, X. Sun, Layer by Layer Assembly of Sandwiched Graphene/SnO2 Nanowire/Carbon Nanostructures with Ultrahigh Lithium Ion Storage Properties. Energy Environ. Sci. 6 (2013) 2900-2906.
J. Wang, J. Yang, Y. Zhang, Y. Li, M. N. Banis, X. Li, R. Li, X. Sun, G. Liang, Interaction of Carbon Coating on LiFePO4: Local Visualization Study of the Influence of Impurity Phases. Adv. Funct. Mater. 23 (2013) 806-814.
K. Chang, D. Geng, X. Li, J. Yang, Y. Tang, M. Cai, R. Li, X. Sun, Ultrathin MoS2/Nitrogen-doped Graphene Nanosheets with Highly Reversible Lithium Storage. Adv. Energy Mater. 3 (2013) 839-844.
J. Yang, J. Wang, Y. Tang, D. Wang, X. Li, Y. Hu, R. Li, G. Liang, T.-K. Sham, X. Sun, LiFePO4/graphene as a Superior Cathode Material for Rechargeable Lithium Batteries: Impact of Stacked Graphene and Unfolded Graphene. Energy Environ. Sci. 6 (2013) 1521-1528. (Back Cover Page, highlighted by "Green Car Congress")
J. Wang, J. Yang, Y. Tang, R. Li, G. Liang, T.-K. Sham, X. Sun, Surface Aging at Olivine LiFePO4: a Direct Visual Observation of Iron Dissolution and the Protection Role of Nano-carbon Coating. J. Mater. Chem. A 1 (2013) 1579-1586. (Highlighted by "Scienceindex" and "Materialsviews"; Selected as a Hot Article for 2013 by Journal of Materials Chemistry A in the "Hot Article 2013 web collection")
X. Meng, X.-Q. Yang, X. Sun, Emerging Applications of Atomic Layer Dposition for Lithium-ion Battery Studies. Adv. Mater. 24 (2012) 3589-3615. (Ten most downloaded articles in June)
J. Wang, R. Li, X. Sun, Understanding and Recent Development of Carbon Coating on LiFePO4 Cathode Material for Lithium-ion Batteries. Energy Environ. Sci. 5 (2012) 5163-5185. (Top 25 most-read Energy & Environmental Science articles from Q2 2012)