J. Mater. Sci. Technol. ›› 2021, Vol. 74: 60-68.DOI: 10.1016/j.jmst.2020.07.041

• Research Article • Previous Articles     Next Articles

Fundamental understanding of high-capacity lithium-excess cathodes with disordered rock salt structure

Hao Lina,b,*(), Beatriz Morenoc, Kamil Kucukd, Sensen Zhanga,e, Shankar Aryald,f, Zheng Lia, Carlo U. Segred,f, Jassiel Rodrigueza, Dhanya Puthusseria, Lirong Caia, Xuechen Jiaog,*(), Vilas G. Pola,*()   

  1. a Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA
    b Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA
    c Canadian Light Source Inc., Saskatoon, Saskatchewan S7N 5A8, Canada
    d Department of Physics & CSRRI, Illinois Institute of Technology, Chicago, IL, 60616 USA
    e School of Metallurgy, Northeastern University, Shenyang 110819, China
    f Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
    g Australian Synchrotron, ANSTO, Clayton, Victoria 3168, Australia
  • Received:2020-05-11 Revised:2020-07-07 Accepted:2020-07-12 Published:2021-05-30 Online:2020-09-28
  • Contact: Hao Lin,Xuechen Jiao,Vilas G. Pol
  • About author:vpol@purdue.edu (V.G. Pol).
    xjiao@ncsu.edu (X. Jiao),
    * Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA. E-mail addresses: haolin.mse@gmail.com (H. Lin),

Abstract:

As a new class of lithium rich cathodes, disordered rock-salt cathodes have been of primary interest, because of their ability to deliver a promisingly high capacity up to 300 mA h/g. Nevertheless, some fundamental issues are yet to be fully understood and a comprehensive mastering of their solid-state chemistry, kinetics and thermal stability is required. Here, we select a high capacity cation-disordered positive electrode- Li1.2Ni0.4Nb0.4O2 as a model compound to study intrinsic reaction mechanism, including charge compensation mechanism, kinetics, thermal stability, and structural evolution. By combining soft and hard X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS) with operando and ex-situ differential scanning calorimetry (DSC), galvanostatic intermittent titration technique (GITT), cyclic voltammetry (CV), and X-ray diffraction (XRD), we present holistic information on disordered rock-salt cathode. This work provides beneficial insights into designing and tailoring new positive electrodes with disordered rock-salt structure.

Key words: Salt-rock structure, Hard/soft XAS, In-situ DSC, Structural evolution