Fabrication and characterization of Li-Mn-Ni-O sputtered thin film high voltage cathodes for Li-ion batteries

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• 作者：Loï ; c Baggetto ; ^{baggettol@ornl.gov} ; Raymond R. Unocic ; Nancy J. Dudney ; Gabriel M. Veith
• 关键词：High voltage spinel cathodes ; Magnetron sputtering ; Thin films ; Layered-spinel composite structure ; Coatings
• 刊名：Journal of Power Sources
• 出版年：2012
• 出版时间：1 August, 2012
• 年：2012
• 卷：211
• 期：Complete
• 页码：108-118
• 全文大小：2282 K

文摘

Li-rich and stoichiometric Li₁Mn_1.5Ni_0.5O₄ (LMNO) cathode films have been successfully prepared by magnetron sputtering. Sputtering from a Li stoichiometric target yields Li-rich films composed of spinel, layered and monoclinic phases. Films obtained from a Li deficient target are mostly made of a spinel phase and little layered material. The resulting cathode thin films have good capacity retention and very high rate capability. The reaction mechanism has been investigated by XRD and HRTEM and evidences the reversible formation of a spinel phase, as is generally found for the powder samples. The film geometry enables us to understand the effect of coatings (ZnO or LiPON). Coating high voltage cathodes reduces the coulombic losses, but at the price of rate performance. Nonetheless, these coated sputtered electrode thin films offer a higher rate capability than other LMNO thin films obtained by other physical vapor deposition techniques.