•  
  •  
 
Nano Research

Article Title

Comprehensive study of a versatile polyol synthesis approach for cathode materials for Li-ion batteries

Authors

Hyeseung Chung, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
Antonin Grenier, Chemistry Department, Stony Brook University, Stony Brook, NY 11794, USA
Ricky Huang, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
Xuefeng Wang, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
Zachary Lebens-Higgins, Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA
Jean-Marie Doux, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
Shawn Sallis, Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
Chengyu Song, National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
Peter Ercius, National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
Karena Chapman, Chemistry Department, Stony Brook University, Stony Brook, NY 11794, USA
Louis F. J. Piper, Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA
Hyung-Man Cho, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
Minghao Zhang, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
Ying Shirley Meng, Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA

Keywords

polyol, cathode, synthesis, nanoparticle, LiNi0.4Mn0.4Co0.2O2 (NMC)

Abstract

This work reports a comprehensive study of a novel polyol method that can successfully synthesize layered LiNi0.4Mn0.4Co0.2O2, spinel LiNi0.5Mn1.5O4, and olivine LiCoPO4 cathode materials. When properly designed, polyol method offers many advantages such as low cost, ease of use, and proven scalability for industrial applications. Most importantly, the unique properties of polyol solvent allow for greater morphology control as shown by all the resulting materials exhibiting monodispersed nanoparticles morphology. This morphology contributes to improved lithium ion transport due to short diffusion lengths. Polyol-synthesized LiNi0.4Mn0.4Co0.2O2 delivers a reversible capacity of 101 and 82 mAh·g−1 using high current rate of 5C and 10C, respectively. It also displays surprisingly high surface structure stability after charge– discharge processes. Each step of the reaction was investigated to understand the underlying polyol synthesis mechanism. A combination of in situ and ex situ studies reveal the structural and chemical transformation of Ni-Co alloy nanocrystals overwrapped by a Mn- and Li-embedded organic matrix to a series of intermediate phases, and then eventually to the desired layered oxide phase with a homogeneous distribution of Ni, Co, and Mn. We envisage that this type of analysis will promote the development of optimized synthesis protocols by establishing links between experimental factors and important structural and chemical properties of the desired product. The insights can open a new direction of research to synthesize high-performance intercalation compounds by allowing unprecedented control of intermediate phases using experimental parameters.

Graphical Abstract

Publisher

Tsinghua University Press

Share

COinS