Title: Quaternary phase diagrams of spinel Li$$_y\square_{1–y}$$Mn$$_x$$Ni$$_{2–x}$$O$$_4$$ and composite cathode voltages for concentration gradient materials

Abstract

Core-shell coating structures and concentration gradient materials may enhance Li-ion battery performance by integrating advantages of core and shell components without introducing unfavorable problems associated with general coatings. The fundamental thermodynamic properties of concentration gradient composite materials are complex due to the multicomponent nature of the problem. Here, we systematically study the thermodynamics of ordering and phase separation in the quaternary spinel Li$$_y\square_{1–y}$$Mn$$_x$$Ni$$_{2–x}$$O$$_4$$ ($$\square$$ means vacancy) system by density functional theory calculations, together with the coupled cluster expansion method with interactions within and between (Li/$$\square$$) and (Mn/Ni) sublattices. On the basis of coupled cluster expansion interactions and Monte Carlo simulations, we calculate quaternary phase diagrams as a function of temperature as well as voltage profiles of single ordered phases and multiphase composite structures. The phase diagram and voltage results are in good agreement with available experimental observations. We also predict a stable high-voltage ordered compound LiMnNiO₄, with a very high delithiation voltage of 4.76 V. For the composite (Mn-rich + Ni-rich) cathode materials, the voltage profiles show combinations of plateaus from each component compound. The computational strategy of combining quaternary phase diagrams with voltage calculations provides a pathway to understand and design concentration gradient materials.

Authors:

Hao, Shiqiang ^[1]; Lu, Zhi ^[1]; Wolverton, Christopher ^[1]

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+ Show Author Affiliations

1. Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

Publication Date:

Tue Jul 19 00:00:00 EDT 2016

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Electrochemical Energy Science (CEES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1388323

Alternate Identifier(s):

OSTI ID: 1264791

Grant/Contract Number:  

AC02-06CH11357; AC0206CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 94; Journal Issue: 1; Related Information: CEES partners with Argonne National Laboratory (lead); University of Illinois, Urbana-Champaign; Northwest University; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; energy storage (including batteries and capacitors); charge transport; materials and chemistry by design; synthesis (novel materials)