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1. Lithium‐Ion Mobility in Layered Oxide Li 2 (La 0.75 Li 0.25 )(Ta 1.5 Ti 0.5 )O 7 Containing Lithium on both Intra and Inter‐Stack Positions

   https://doi.org/10.1002/ejic.202100950  

   Fanah, Selorm Joy ; Ramezanipour, Farshid ( February 2022 , European Journal of Inorganic Chemistry)

   With the aid of neutron diffraction and electrochemical impedance spectroscopy, we have demonstrated the effect of the increase in lithium concentration and distribution on Li‐ion conductivity. This has been done through the synthesis of a layered oxide Li₂(La_0.75Li_0.25)(Ta_1.5Ti_0.5)O₇, with the so‐called Ruddlesden‐Popper type structure, where bilayer stacks of (Ta/Ti)O₆octahedra are separated by lithium ions, located in inter‐stack spaces. There are also intra‐stack spaces that are occupied by a mixture of La and Li, as confirmed by neutron diffraction. The distribution of lithium over both inter‐ and intra‐stack positions leads to the enhancement of Li‐ion conductivity in Li₂(La_0.75Li_0.25)(Ta_1.5Ti_0.5)O₇compared to Li₂La(TaTi)O₇, which has a lower concentration of lithium ions, located only in inter‐stack spaces. The analyses of real and imaginary components of electrochemical impedance data confirm the enhanced mobility of ions in Li₂(La_0.75Li_0.25)(Ta_1.5Ti_0.5)O₇. While the Li‐ion conductivity needs further improvement for practical applications, the success of the strategy implemented in this work offers a useful methodology for the design of layered ionic conductors.

    

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2. C 9 N 4 and C 2 N 6 S 3 monolayers as promising anchoring materials for lithium–sulfur batteries: weakening the shuttle effect via optimizing lithium bonds

   https://doi.org/10.1039/D1CP01022K  

   Dong, Yinan ; Xu, Bai ; Hu, Haiyu ; Yang, Jiashu ; Li, Fengyu ; Gong, Jian ; Chen, Zhongfang ( June 2021 , Physical Chemistry Chemical Physics)

   The notorious polysulfide shuttle effect is a crucial factor responsible for the degradation of Li-S batteries. A good way to suppress the shuttle effect is to effectively anchor dissoluble lithium polysulfides (LPSs, Li 2 S n ) on appropriate substrates. Previous studies have revealed that Li of Li 2 S n is prone to interact with the N of N-containing materials to form Li–N bonds. In this work, by means of density functional theory (DFT) computations, we explored the possibility to form Li bonds on ten different N-containing monolayers, including BN, C 2 N, C 2 N 6 S 3 , C 9 N 4 , a covalent triazine framework (CTF), g -C 3 N 4 , p -C 3 N 4 , C 3 N 5 , S -N 2 S, and T -N 2 S, by examining the adsorption behavior of Li 2 S n ( n = 1, 2, 3, 4, 6, 8) on these two-dimensional (2D) anchoring materials (AMs), and investigated the performance of the formed Li bonds (if any) in inhibiting the shuttle effect. By comparing and analyzing the nitrogen content, the N-containing pore size, charge transfer, and Li bonds, we found that the N content and N-containing pore size correlate with the number of Li bonds, and the formed Li–N bonds between LPSs and AMs correspond well with the adsorption energies of the LPSs. The C 9 N 4 and C 2 N 6 S 3 monolayers were identified as promising AMs in Li-S batteries. From the view of Li bonds, this work provides guidelines for designing 2D N-containing materials as anchoring materials to reduce the shuttle effect in Li-S batteries, and thus improving the performance of Li-S batteries. 

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3. The Nature of Lithium Bonding in C 2 H 2 Li 2 , C 6 Li 6 , and Lithium Halide Dimers

   https://doi.org/10.1021/acs.organomet.9b00683  

   Liu, Yameng ; Peng, Bin ; Wang, Xiao ; Xie, Yaoming ; Schaefer, Henry F. ( November 2019 , Organometallics)
4. Conformational Preference of Lithium Polysulfide Clusters Li 2 S x ( x = 4–8) in Lithium–Sulfur Batteries

   https://doi.org/10.1021/acs.inorgchem.3c04537  

   Peng, Xinru ; Li, Jiayao ; Dang, Jingshuang ; Yin, Shiwei ; Zheng, Hengyan ; Wang, Changwei ; Mo, Yirong ( February 2024 , Inorganic Chemistry)
5. Fe 3 C/nanocarbon‐Enabled Lithium Dendrite Mitigation in Lithium–Sulfur batteries

   https://doi.org/10.1002/smll.202308261  

   Chen, Ruoxi ; Zhou, Yucheng ; Li, Xiaodong ( December 2023 , Small)

   Lithium dendrite‐induced short circuits and material loss are two major obstacles to the commercialization of lithium–sulfur (Li−S) batteries. Here, a nanocarbon composite consisting of cotton‐derived Fe₃C‐encapsulated multiwalled carbon nanotubes (Fe₃C‐MWCNTs) and graphene effectively traps polysulfides to suppress lithium dendrite growth is reported. Machine learning combined with molecular dynamics (MD) simulations unveils a new polysulfide‐induced lithium dendrite formation mechanism: the migration of polysulfides away from the anode drags out lithium protrusions through localized lattice distortion of the lithium anode and traps lithium ions in the surrounding electrolyte, leading to lithium dendrite formation. The Li−S battery, constructed using the composite of cotton‐derived Fe₃C‐MWCNTs and graphene that serves as both the sulfur host and the anode interlayer, exhibits exceptional cycling stability, impressive capacity retention, and effective mitigation of lithium dendrite formation. The findings offer valuable strategies to prevent lithium dendrite formation and enhance understanding of lithium dendrite growth in Li−S batteries.

    

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