10.1021/acs.nanolett.5b00388.s001 Yanliang Liang Yanliang Liang Hyun Deog Yoo Hyun Deog Yoo Yifei Li Yifei Li Jing Shuai Jing Shuai Hector A. Calderon Hector A. Calderon Francisco Carlos Robles Hernandez Francisco Carlos Robles Hernandez Lars C. Grabow Lars C. Grabow Yan Yao Yan Yao Interlayer-Expanded Molybdenum Disulfide Nanocomposites for Electrochemical Magnesium Storage American Chemical Society 2015 Mg diffusion behavior Mg storage materials novel intercalation chemistry MoS 2 report interlayer expansion Electrochemical Magnesium StorageMg interlayer expansion approach expansion boosts Mg diffusivity divalent Mg ion 2015-03-11 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Interlayer_Expanded_Molybdenum_Disulfide_Nanocomposites_for_Electrochemical_Magnesium_Storage/2187859 Mg 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 MoS<sub>2</sub>, 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 MoS<sub>2</sub> 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 MoS<sub>2</sub> 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.