ALD is ideal for coating high surface area electrodes with either protective films or active charge-storage films. We were the first to demonstrate that ALD protective films on either the cathode or anode electrode can dramatically improve the capacity of Li ion batteries [1,2]. This research was performed in collaboration with Prof. Sehee Lee in Mechanical Engineering and the National Renewable Energy Laboratory (NREL). Metal oxide charge-storage films coated on electrically conducting electrodes have also been used to fabricate high energy storage Li ion batteries [3,4].
We are also working on metal oxide charge-storage films on electrically conducting electrodes for supercapacitors. The charge-storage capacity of MnO2 has been examined in collaboration with Prof. Charles Musgrave in Chemical Engineering using density functional theory (DFT) methods [5]. Experimental work has also confirmed that MnO2 has a high Na+ charge storage capacity [6]. We are hopeful that Na+ charge storage in MnO2 can also be useful for water desalination using capacitive deionization (CDI).
1. Y.S. Jung, A.S. Cavanagh, A.C. Dillon, M.D. Groner, S.M. George and S.H. Lee, "Enhanced Stability of LiCoO2 Cathodes in Lithium-ion Batteries Using Surface Modification by Atomic Layer Deposition", J. Electrochem. Soc. 157, A75-A81 (2010).
2. Y.S. Jung, A.S. Cavanagh, A.C. Dillon, M.D. Groner, S.M. George and S.H. Lee, "Ultrathin Direct Atomic Layer Deposition on Composite Electrodes is Critical for Highly Durable and Safe Li-Ion Batteries ", Adv. Mater. 22, 2172-2176 (2010).
3. D.M. Piper, J.J. Travis, M.J. Young, S.B. Son, S.C. Kim, K.H. Oh, S.M. George, C.M. Ban and S.H. Lee, “Reversible High-Capacity Si Nanocomposite Anodes for Lithium Ion Batteries Enabled by Molecular Layer Deposition”, Adv. Mater. 26, 1596-1601 (2014).
4. Yang He, Daniela Molina Piper, Meng Gu, Jonathan J. Travis, Steven M. George, Se-Hee Lee, Arda Genc, Lee Pullan, Jun Liu, Scott X. Mao Ji-Guang Zhang, Chunmei Ban and Chongmin Wang, "In Situ Transmission Electron Microscopy Probing of Native Oxide and Artificial Layer on Silicon Nanoparticles for Lithium Ion Battery", ACS Nano 8, 11816-11823 (2014).
5. Matthias J. Young, Aaron M. Holder, Steven M. George and Charles B. Musgrave, “Charge Storage in Cation Incorporated α-MnO2”, Chem. Mater. 27, 1172-1180 (2015).
6. Matthias J. Young, Markus Neuber, Andrew C. Cavanagh, Huaxing Sun, Charles B. Musgrave and Steven M. George, “Sodium Charge Storage in Thin Films of MnO2 Derived by Electrochemical Oxidation of MnO Atomic Layer Deposition Films”, J Electrochem. Soc. 162, A2753-A2761 (2015).