Probing Mechanistic Insights into Highly Efficient Lithium Storage of C60 Fullerene Enabled via Three-Electron-Redox Chemistry

Enhancing Li-Ion Battery Anodes: Synthesis, Characterization, and Electrochemical Performance of Crystalline C60 Nanorods with Controlled Morphology and Phase Transition

Recently, C60 has emerged as a promising anode material for Li-ion batteries, attracting significant interest due to its excellent lithium storage capacity. The electrochemical performance of C60 as an anode is largely dependent on its internal crystal structure, which is significantly influenced by the synthesis method and corresponding conditions. However, there have been few reports on how the synthesis process affects the crystal structure and Li+ storage capacity of C60. This study used the liquid-liquid interface precipitation method and a low-temperature annealing process to fabricate one-dimensional C60 nanorods (NRs). We thoroughly investigated synthesis conditions, including the growth time, drying temperature, annealing time, and annealing atmosphere. The results demonstrate that these synthesis conditions directly impact the morphology, phase transition, and electrochemical efficiency of pure C60 NRs. Remarkably, the hexagonal close-packed structural C60 NRs-6012h, in a metastable form, exhibits a reversible Li+ storage capacity as an anode material in Li-ion batteries. Furthermore, the face-centered cubic C60 NRs-603001h electrode shows significantly enhanced rate performance and long-cycle stability. A discharge-specific capacity of 603 mAh g-1 was maintained after 2000 cycles at a current density of 2 A g-1. This study elucidates the effect of synthesis conditions on C60 crystals, offering an effective strategy for preparing high-performance C60 anode materials.

Boosting Perovskite Solar Cells Efficiency and Stability: Interfacial Passivation of Crosslinked Fullerene Eliminates the "Burn-in" Decay

Perovskite solar cells (PSCs) longevity is nowadays the bottleneck for their full commercial exploitation. Although lot of research is ongoing, the initial decay of the output power - an effect known as "burn-in" degradation happening in the first 100 h - is still unavoidable, significantly reducing the overall performance (typically of >20%). In this paper, the origin of the "burn-in" degradation in n-i-p type PSCs is demonstrated that is directly related to Li⁺ ions migration coming from the SnO₂ electron transporting layer visualized by time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements. To block the ion movement, a thin cross-linked [6,6]-phenyl-C61-butyric acid methyl ester layer on top of the SnO₂ layer is introduced, resulting in Li⁺ immobilization. This results in the elimination of the "burn-in" degradation, showing for the first time a zero "burn-in" loss in the performances while boosting device power conversion efficiency to >22% for triple-cation-based PSCs and >24% for formamidinium-based (FAPbI₃ ) PSCs, proving the general validity of this approach and creating a new framework for the realization of stable PSCs devices.

Novel Li3 VO4 Nanostructures Grown in Highly Efficient Microwave Irradiation Strategy and Their In-Situ Lithium Storage Mechanism

The investigation of novel growth mechanisms for electrodes and the understanding of their in situ energy storage mechanisms remains major challenges in rechargeable lithium-ion batteries. Herein, a novel mechanism for the growth of high-purity diversified Li3 VO4 nanostructures (including hollow nanospheres, uniform nanoflowers, dispersed hollow nanocubes, and ultrafine nanowires) has been developed via a microwave irradiation strategy. In situ synchrotron X-ray diffraction and in situ transmission electron microscope observations are applied to gain deep insight into the intermediate Li3+ x VO4 and Li3+ y VO4 phases during the lithiation/delithiation mechanism. The first-principle calculations show that lithium ions migrate into the nanosphere wall rapidly along the (100) plane. Furthermore, the Li3 VO4 hollow nanospheres deliver an outstanding reversible capacity (299.6 mAh g-1 after 100 cycles) and excellent cycling stability (a capacity retention of 99.0% after 500 cycles) at 200 mA g-1 . The unique nanostructure offers a high specific surface area and short diffusion path, leading to fast thermal/kinetic reaction behavior, and preventing undesirable volume expansion during long-term cycling.