Lithium metal negative electrode is considered as the most promising candidate material for rechargeable lithium-based batteries, but the uncontrollable lithium dendrite hinders its further application. In recent years, mxene has promoted the rapid development of dendrite free metal lithium negative electrode. Since Professor Yang Shubin's team published the article on mxene used for metal lithium negative electrode, mxene with horizontal and vertical arrangement structure has also been further applied to the research of metal lithium negative electrode and achieved good performance. Through a large number of studies of mxene on metal lithium anode, it is found that the vertically arranged mxene metal lithium composite anode has higher capacity and energy density. However, in the vertically arranged mxene, due to the extremely small radius of curvature, the tip discharge effect is significantly amplified, resulting in the easy deposition of metal lithium on the electrode surface and the formation of dendrites. Therefore, in order to solve this problem, mxene thin films with low curvature and flexible sine wave like structure were prepared and applied to metal lithium anode.
Introduction to achievements
Recently, the team of Professor Yang Shubin of Beijing University of Aeronautics and Astronautics innovated and prepared mxene thin films with low curvature flexible sine wave like structure and applied them to metal lithium anode. Firstly, the theoretical simulation study of COMSOL multiphysics shows that the curvature of the electrode surface has an important effect on the nucleation and growth behavior of lithium metal. In this study, the influence of the groove model on the electrodeposition behavior of lithium metal is systematically studied by establishing a groove model, which provides a new idea for obtaining high-capacity dendrite free lithium metal anode. Under the guidance of the theoretical model, mxene thin films with low curvature and sine like structure were designed and prepared. The nucleation and growth of metal lithium on mxene thin films with sine like structure were systematically studied by in-situ optical microscopy and SEM.
This achievement was published online in the international top-level journal advanced energy materials (impact factor 29.698), with the title of "optimizing lightning rod effect of lithium anodes via sine wave analog mxene layers".
Text guide
Fig. 1. Schematic diagram of deposition process of metal lithium on (a) type sine wave structure (low curvature) and (b) vertical array structure (high curvature) substrates, respectively.
Fig. 2. Mxene thin film with sine like structure (a) schematic diagram of preparation process, (b) front SEM and (c) cross-sectional SEM. (d) The impedance response of mxene thin films with sinusoidal like structure and planar structure was measured.
Fig. 3. SEM images of mxene films with sine like structure after deposition of (a) 0.5 MAH cm-2, (b) 4 MAH cm-2 and (c) 8 MAH cm-2, respectively. (d) COMSOL multiphysics simulation of different deposition processes of metal lithium in mxene thin films with sinusoidal structure. In situ optical photos of the deposition process of metallic lithium on (E) mxene films with sinusoidal structure and (f) metallic copper surfaces.
Fig. 4. (a) contact angle test and (b) nucleation overpotential test of mxene films with sinusoidal like structure, mxene films with planar structure and metallic copper. (c) The cycle performance of the cell is influenced by the sine like structure mxene Li, the planar structure mxene Li and the metal Cu Li. (d) The magnification performance of mxene Li with sine like structure.
Fig. 5 photos of mxene Li soft pack battery with sinusoidal wave structure (a) and (b). (c) The cycle performance of the sine like structure mxene Li soft pack battery and (d) the planar structure mxene Li soft pack battery under different bending states. (e) The deep charge and deep discharge performance of mxene Li with sine wave like structure.
Figure 6. Sine like structure mxene Li / / LFP, planar structure mxene Li / / FLP and Cu Li / / FLP (a) cycle performance at 34 Ma g-1, (b) magnification performance and (c) cycle performance at 1088 Ma g-1.
summary
In this study, mxene (ti3c2tx) thin films with sinusoidal like structure were obtained by dispersing mxene aqueous solution onto the cross-sectional surface of metal coils and then drying at room temperature. COMSOL multiphysics simulation results show that the low curvature of the mxene thin film with a sine like structure can effectively homogenize the distribution of lithium ions and electric fields, and effectively eliminate the tip discharge effect on the electrode surface during lithium deposition. Therefore, the mxene thin film with sine wave like structure has a low lithium nucleation overpotential (0.05 Ma cm − 2 ~ 13.5 MV), a deep charge and deep discharge capacity of 40 MAH cm − 2, and a long cycle life of 1250 H. In addition, the full cell composed of mxene Li composite negative electrode and LiFePO4 positive electrode based on the sine like structure has a cycle life of 420 times at a current density of 1088 Ma g − 1.
Literature link
https://doi.org/10.1002/aenm.202201181
Special thanks to the author for his strong support
[introduction to the first author]
Gu Jianan, doctor, associate professor of North China Electric Power University (Beijing). In June 2020, he received a doctorate degree in materials science from Beijing University of Aeronautics and Astronautics (Tutor: Professor Yang Shubin). In the same year, he entered Beihang University of physics to engage in post doctoral research (cooperative Tutor: Professor Geng Lisheng). During his doctoral period, he won two national scholarships for doctoral students, the innovation and entrepreneurship scholarship of the Ministry of industry and information technology, Beijing excellent doctoral graduates, and Beihang excellent doctoral theses. He presided over the youth fund of the National Natural Science Foundation of China, the 68th batch of general projects of the China Post Doctoral science foundation, and was selected into the 5th batch of post doctoral innovative talents support plan. He participated in the outstanding youth fund of the National Natural Science Foundation of China, general projects and key R & D projects of the Ministry of science and technology. In recent years, it has been published in the international famous journal adv Mater.、Adv. Energy. Mater.、Adv. Funct. Mater.、 ACS Nano and small have published more than 20 SCI papers. The research direction is controllable preparation of new ultra-thin two-dimensional materials (mxenes) and electrochemical energy storage research (lithium, sodium ion battery electrode materials, lithium metal anode, zinc metal anode, etc.).
[brief introduction of corresponding author]
Yang Shubin, Ph.D., Professor of Beijing University of Aeronautics and Astronautics, national outstanding youth. In 2008, he graduated from Beijing University of chemical technology with a doctor's degree. He has been engaged in scientific research at the Max Planck Institute of polymer in Germany and Rice University in the United States. In 2013, he joined Beijing University of Aeronautics and Astronautics, engaged in research work in the field of two-dimensional materials and energy storage. He has worked in nature, nature commun., acc Chem. Res.、Adv. Mater.、Angew. Chem. Int. ed. and other international high-level journals and magazines have published more than 100 SCI papers and cited more than 15000 times. Many articles have been selected into the top 1% of the cited papers in ESI. In 2016, it won the excellent youth fund of the National Natural Science Foundation of China. Since 2017, he has been nominated by clarivate analytics and Elsevier as "global highly cited scientist" and "Chinese highly cited scientist" respectively. In 2021, it won the National Natural Science Fund for Distinguished Young Scholars. The research direction is the controllable synthesis and Electrochemical Performance Research of two-dimensional layered materials (mxenes, graphene, TMDs) (metal anode).
