Solvation-Free Li+ Lewis Acid Enhancing Reaction: Kinetic Study of [5,6]-Li+@PCBM to [6,6]-Li+@PCBM

Neuron-Like Silicone Nanofilaments@Montmorillonite Nanofillers of PEO-Based Solid-State Electrolytes for Lithium Metal Batteries with Wide Operation Temperature

Poly(ethylene oxide) (PEO)-based composite solid electrolytes (CSEs) are promising to accelerate commercialization of solid-state lithium metal batteries (SSLMBs). Nonetheless, this is hindered by the CSEs' limited ion conductivity at room temperature. Here, we propose design, synthesis, and application of the bioinspired neuron-like nanofillers for PEO-based CSEs. The neuron-like superhydrophobic nanofillers are synthesized by controllably grafting silicone nanofilaments onto montmorillonite nanosheets. Compared to various reported fillers, the nanofillers can greatly improve ionic conductivity (4.9×10-4 S cm-1, 30 °C), Li+ transference number (0.63), oxidation stability (5.3 V) and mechanical properties of the PEO-based CSEs because of the following facts. The distinctive neuron-like structure and the resulting synaptic-like connections establish numerous long-distance continuous channels over various directions in the PEO-based CSEs for fast and uniform Li+ transport. Consequently, the assembled SSLMBs with the CSEs and LiFePO4 or NCM811 cathodes display superior cycling stability over a wide temperature range of 50 °C to 0 °C. Surprisingly, the pouch batteries with the large-scale prepared CSEs kept working after being repeatedly bent, folded, cut or even punched in air. We believe that design of neuron-like nanofillers is a viable approach to produce CSEs with high room temperature ionic conductivity for SSLMBs.

Enhanced reactivity of Li+@C60 toward thermal [2 + 2] cycloaddition by encapsulated Li+ Lewis acid

Lithium ion-endohedral fullerene (Li+@C60), a member of the burgeoning family of ion-endohedral fullerenes, holds substantial promise for diverse applications owing to its distinctive ionic properties. Despite the high demand for precise property tuning through chemical modification, there have been only a few reports detailing synthetic protocols for the derivatization of this novel material. In this study, we report the synthesis of Li+@C60 derivatives via the thermal [2 + 2] cycloaddition reaction of styrene derivatives, achieving significantly higher yields of monofunctionalized Li+@C60 compared to previously reported reactions. Furthermore, by combining experimental and theoretical approaches, we clarified the range of applicable substrates for the thermal [2 + 2] cycloaddition of Li+@C60, highlighting the expanded scope of this straightforward and selective functionalization method.

Sequential click modification of a lithium-ion endohedral fullerene connecting small molecules through a dieneazide linker

A versatile method for the chemical modification of a lithium-ion endohedral fullerene (Li⁺@C₆₀) to connect various small molecules is described. The designed dieneazide linker enables the facile connection of Li⁺@C₆₀ with small molecules bearing a terminal alkyne via Huisgen annulation and a subsequent Diels-Alder reaction. This strategy significantly expands the diversity of small molecules to be attached by Li⁺@C₆₀.

Synthesis of neutral Li-endohedral PCBM: an n-dopant for fullerene derivatives

Li@PCBM, the first neutral Li@C₆₀ derivative, was synthesized. The Li@PCBM exists in a monomer-dimer equilibrium in solution but as a monomer in the PCBM matrix. The fully dispersed Li@PCBM n-doped the surrounding empty PCBM, raising the Fermi level by 0.13 eV compared with the undoped PCBM film. The hybrid films were utilized as an ETL for PSCs, promoting the efficiency of the device.

Dehydrogenation of ammonia-borane to functionalize neutral and Li+-encapsulated C60, C70 and C36 fullerene cages: a DFT approach

Mechanistic investigations into the functionalization of three fullerene cages, viz. C₆₀, C₇₀, and C₃₆ through dehydrogenation of ammonia-borane (AB) have been conducted using Density Functional Theory (DFT). In this process of functionalization, different ring fusions, namely (6-6), (6-5) positions for C₆₀ and C₇₀, and an additional (5-5) for C₃₆ fullerene have been investigated. The optimized geometries of all the complexes and transition states have been characterized using the M06-2X functional in conjunction with the 6-31G(d) basis set. The effect of Li⁺-encapsulation on the energetics and activation barriers of H₂ attachment has also been examined. Although the process of functionalization of neutral fullerenes proceeds extensively through concerted pathways, a step-wise route has been observed for the encapsulated systems. NPA charge analysis and Wiberg bond index (WBI) have been used in order to detect the change in the nature of participating hydrogen atoms and validate the variation in the bond order of the C-C connectivity respectively upon hydrogenation. GCRD parameters have also been calculated to explicate the electronic properties of the hydrogenated products. The (6-6) hydrogenation is observed to be favoured thermodynamically and kinetically for both neutral and Li⁺-encapsulated C₆₀ and C₇₀, while (5-5) is found to be the most preferred site for C₃₆ systems. Our theoretical exploration suggests that the covalent functionalization of the fullerene cages can be done successfully viaAB resulting in the stabilization of these systems. In short, the present work will provide a general idea about the detailed mechanism related to the functionalization of fullerene cages, which will further motivate researchers in fullerene chemistry.