nl5b00388_si_001.pdf (1.2 MB)
Interlayer-Expanded Molybdenum Disulfide Nanocomposites for Electrochemical Magnesium Storage
journal contribution
posted on 2015-03-11, 00:00 authored by Yanliang Liang, Hyun Deog Yoo, Yifei Li, Jing Shuai, Hector
A. Calderon, Francisco Carlos Robles Hernandez, Lars C. Grabow, Yan YaoMg
rechargeable batteries (MgRBs) represent a safe and high-energy battery
technology but suffer from the lack of suitable cathode materials
due to the slow solid-state diffusion of the highly polarizing divalent
Mg ion. Previous methods improve performance at the cost of incompatibility
with anode/electrolyte and drastic decrease in volumetric energy density.
Herein we report interlayer expansion as a general and effective atomic-level
lattice engineering approach to transform inactive intercalation hosts
into efficient Mg storage materials without introducing adverse side
effects. As a proof-of-concept we have combined theory, synthesis,
electrochemical measurement, and kinetic analysis to improve Mg diffusion
behavior in MoS2, which is a poor Mg transporting material
in its pristine form. First-principles simulations suggest that expanded
interlayer spacing allows for fast Mg diffusion because of weakened
Mg–host interactions. Experimentally, the expansion was realized
by inserting a controlled amount of poly(ethylene oxide) into the
lattice of MoS2 to increase the interlayer distance from
0.62 nm to up to 1.45 nm. The expansion boosts Mg diffusivity by 2
orders of magnitude, effectively enabling the otherwise barely active
MoS2 to approach its theoretical storage capacity as well
as to achieve one of the highest rate capabilities among Mg-intercalation
materials. The interlayer expansion approach can be leveraged to a
wide range of host materials for the storage of various ions, leading
to novel intercalation chemistry and opening up new opportunities
for the development of advanced materials for next-generation energy
storage.