TY - JOUR
T1 - Ultrathin lithium-ion conducting coatings for increased interfacial stability in high voltage lithium-ion batteries
AU - Park, Joong Sun
AU - Meng, Xiangbo
AU - Elam, Jeffrey W.
AU - Hao, Shiqiang
AU - Wolverton, Christopher
AU - Kim, Chunjoong
AU - Cabana, Jordi
PY - 2014/5/27
Y1 - 2014/5/27
N2 - Ultrathin conformal coatings of the lithium ion conductor, lithium aluminum oxide (LiAlO2), were evaluated for their ability to improve the electrochemical stability of LiNi0.5Mn1.5O 4/graphite Li-ion batteries. Electrochemical impedance spectroscopy confirmed the ion conducting character of the LiAlO2 films. Complementary simulations of the activation barriers in these layers match experimental results very well. LiAlO2 films were subsequently separately deposited onto LiNi0.5Mn1.5O4 and graphite electrodes. Increased electrochemical stability was observed, especially in the full cells, which was attributed to the role of the coatings as physical barriers against side reactions at the electrode-electrolyte interface. By comparing data from full cells where the coatings were applied to either electrode, the dominating failure mechanism was found to be the diffusion of transition metal ions from the cathode to the anode. The LiNi 0.5Mn1.5O4/graphite full cell with less than 1 nm LiAlO2 on the positive electrode exhibited a discharge capacity of 92 mAh/g at C/3 rate. The chemical underpinnings of stable performance were revealed by soft X-ray absorption spectroscopy. First, both manganese and nickel were detected on the graphite electrode surfaces, and their oxidation states were determined as +2. Second, the ultrathin coatings on the anode alone were found to be sufficient to significantly reduce this deleterious process.
AB - Ultrathin conformal coatings of the lithium ion conductor, lithium aluminum oxide (LiAlO2), were evaluated for their ability to improve the electrochemical stability of LiNi0.5Mn1.5O 4/graphite Li-ion batteries. Electrochemical impedance spectroscopy confirmed the ion conducting character of the LiAlO2 films. Complementary simulations of the activation barriers in these layers match experimental results very well. LiAlO2 films were subsequently separately deposited onto LiNi0.5Mn1.5O4 and graphite electrodes. Increased electrochemical stability was observed, especially in the full cells, which was attributed to the role of the coatings as physical barriers against side reactions at the electrode-electrolyte interface. By comparing data from full cells where the coatings were applied to either electrode, the dominating failure mechanism was found to be the diffusion of transition metal ions from the cathode to the anode. The LiNi 0.5Mn1.5O4/graphite full cell with less than 1 nm LiAlO2 on the positive electrode exhibited a discharge capacity of 92 mAh/g at C/3 rate. The chemical underpinnings of stable performance were revealed by soft X-ray absorption spectroscopy. First, both manganese and nickel were detected on the graphite electrode surfaces, and their oxidation states were determined as +2. Second, the ultrathin coatings on the anode alone were found to be sufficient to significantly reduce this deleterious process.
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U2 - 10.1021/cm500512n
DO - 10.1021/cm500512n
M3 - Article
AN - SCOPUS:84901394062
SN - 0897-4756
VL - 26
SP - 3128
EP - 3134
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 10
ER -