Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour Manganese phosphate coated Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 cathode material: Towards superior cycling stability at elevated temperature and high voltage Zhen Chen a,b , Guk-Tae Kim b,c,* , Yang Guang d , Dominic Bresser b,c , Thomas Diemant e , Yizhong Huang d , Mark Copley f , Rolf Jürgen Behm e , Stefano Passerini b,c,** , Zexiang Shen g,h,*** a Energy Research Institute (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, 637553, Singapore b Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany c Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021, Karlsruhe, Germany d School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore e Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081, Ulm, Germany f Johnson Matthey Technology Centre, Reading, RG4 9NH, UK g School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore h Energy Research Institute (ERI@N), Nanyang Technological University, 637553, Singapore HIGHLIGHTS • MnPO 4 coated LiNi 0.6 Co 0.2 Mn 0.2 O 2 offers enhanced thermal stability. • The MnPO 4 coating ensures the struc- tural integrity of the active material. • MnPO 4 coating of LiNi 0.6 Co 0.2 Mn 0.2 O 2 enable the use of aqueous binders. • The MnPO 4 coating of LiNi 0.6 Co 0.2 Mn 0.2 O 2 suppresses side reactions with the electrolyte. • MnPO 4 -coated LiNi 0.6 Co 0.2 Mn 0.2 O 2 well performs at elevated temperature and high voltage. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: MnPO 4 coating Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 Ni-rich Cathode Lithium-ion battery ABSTRACT Nickel-rich Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 is considered to be the next step forward towards the realization of high- energy lithium-ion batteries and has, thus, attracted intensive attention recently. However, achieving long-term cycling stability at elevated temperatures and voltages still remains a formidable challenge for practical appli- cations. In this work, we successfully synthesized MnPO 4 -coated Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 (MP-NCM) with an ad- vantageously low coating content of only 1 wt% while providing substantially enhanced electrochemical per- formance and outstanding cycling stability. This improvement is ascribed to the MnPO 4 coating, acting as an ideal protective layer to dramatically reduce the occurring side reactions with the electrolyte, especially at higher temperatures and cut-off voltages. By preventing the direct contact between the cathode active material and the electrolyte, the presence of the coating layer reduces the transition metal dissolution, thus, yielding good structural integrity upon cycling, while its amorphous nature allows for an enhanced apparent lithium ion diffusion, i.e., lithium de-/insertion kinetics. Additionally, the strong covalent bonding of the PO 4 -group con- tributes to an increased thermal stability and the high voltage performance of MP-NCM. On the basis of our https://doi.org/10.1016/j.jpowsour.2018.09.049 Received 28 July 2018; Received in revised form 14 September 2018; Accepted 16 September 2018 * Corresponding author. Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany. ** Corresponding author. Helmholtz Institute Ulm (HIU), Helmholtzstrasse 11, D-89081, Ulm, Germany. *** Corresponding author. School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore. E-mail addresses: guk-tae.kim@kit.edu (G.-T. Kim), stefano.passerini@kit.edu (S. Passerini), zexiang@ntu.edu.sg (Z. Shen). Journal of Power Sources 402 (2018) 263–271 0378-7753/ © 2018 Elsevier B.V. All rights reserved. T