Prof. Yue Ma group (School of Materials Science and Engineering, Northwestern Polytechnical University) recently published a paper entitled “Molten-Li Infusion of Ultra-Thin Interfacial Modification Layer towards the Highly-Reversible, Energy-Dense Metallic Batteries” on Energy Storage Materials (2022) 45: 796-804. In this research, they proposed an ultra-thin interfacial composite layer derived from the core-shell MOF precursor to furnish the Cu foil. The in-situ grown CNTs threaded from the interior Co-centers could enhance the structural robustness of the dodecahedron storage units in the interfacial layer; while the atomically dispersed Zn species riveted on the exterior could absorb the Li ions as the “magnet” for the controlled molten-Li infusion. the as-constructed single-layer pouch cell realized the simultaneous high energy density and cycling endurance at the extreme rates. With further real-time phasic monitor and post-mortem morphological evaluation of the full cell model, the reversible dynamic lattice breathing of the NMC-811 cathode as well as the restrained dendrite growth of the anode substrate could be observed, as showed in Figure 1.
The unstable dynamic properties and the safety risks of the metallic anodes hinder their practical deployment in the energy-dense battery system with limited cation source (lean electrolyte in the anode-free/anode-less model).So far, the high-capacity merit of the metallic lithium has yet to be fully realized due to the insufficient utilization of the excessive pre-stored lithium and irreversible cation consumption upon cycling, despite of the intensive research efforts towards the Li deposit regulation. In this sense, the necessary consideration of the metal plating behavior, precise control of the unpaired metallic mass/volume and cycling durability challenges the practical construction of energy-dense metallic battery systems. In this work, they investigate these questions with MOF derived carbonaceous materials as the interfacial modification layers. The interfacial layer effectively modified the Cu foil substrate to regulate the Li nucleation pattern, thereby preventing the dendrite growth and furnishing the reversible plating/stripping process. The single-layer pouch cell was constructed by integrating the Co@Zn-CNT-Cu anode with the precise control of the molten-Li infusion (0.5×excess) and the LiNi0.8Mn0.1Co0.1O2 (NMC-811) cathode, which exhibits a balanced cycling endurance (90.7% reversible capacity retention upon 150 cycles) as well as the impressive energy/power output without sacrificing the electroactive mass at the penalty. This interfacial modification approach effectively maximizes the Li utilization degree on the device level, which encourages the practical exploitation of the energy-dense metallic battery systems.
Figure 1 The dynamic evolution of the as-constructed single-layer pouch cell.
The main novelties of present work are as following:
A stepwise pyrolysis process transforms the epitaxial grown, core-shell MOF structure (ZIF-67@ZIF-8) into the lithiophilic dodecahedrons with the CNTs network threaded from the interior cobalt centers as the structural support (Co@Zn-CNT).
The ultra-thin Co@Zn-CNT layer (6.3 μm, 0.35 mg cm−2) modified Cu foil in which the atomically dispersed Zn species could absorb the Li ions as the “magnet”, which exhibits a stable coulombic efficiency over 99.8% at 2 mA cm−2 and a high-areal-capacity value up to 10 mA h cm−2.
The real-time phase evolution of the as-paired NMC-811 cathode in the as-assembled single-layer pouch cell was tracked through the transmission-mode operando X-ray diffraction, validating the pivotal influence of the Li ion utilization degree on the device level.
Prof. Yue Ma group in School of Materials Science and Engineering, Northwestern Polytechnical University, has been working on energy storage materials, and using a variety of in-situ/ex-situ monitoring techniques to reveal the dynamic changes of electrode electronic structure, crystal structure and surface interface reactions in electrochemical systems and battery storage mechanisms. His research team is now focusing on lithium/sodium metal battery, flexible all-solid energy storage system, silicon carbon anode material industrialization technology, as well as synchrotron radiation photoelectron spectroscopy and in situ XRD detection technology. In this work, Prof. Yue Ma is the corresponding authors, Ting Zhao is the first authors. This work is supported by the National Natural Science Foundation of China (52173229), the Natural Science Foundation of Shaanxi (2019KJXX-099, 2020YZ0037, and 2019QYPY-194), the Fundamental Research Funds for the Central Universities (3102019JC005), Key R&D Program of Shaanxi (No. 2019ZDLGY04-05), and the Development and Industrialization Fund (2020KJRC0120).
The article link is as follows: https://doi.org/10.1016/j.ensm.2021.12.032
Author: Yue Ma
Reviewer: Hongqiang Wang，Wei Liu