Phase Engineering Of Metallic MoS₂ And Its Industrial Adaptation Of High-performance Supercapacitor Electrodes

Under the trend of“carbon neutrality,carbon peak”,the development of supercapacitor has received significant attention around the world.With the rapid development of two-dimensional nanomaterials,metallic phase molybdenum disulfide（1T Mo S₂）shows excellent volumetric energy storage performance as supercapacitor electrodes.However,current studies mainly focus on the limit performance of noval nanomaterials,and lack exploration and adaptation in actual industrialization.In order to drive 1T Mo S₂ from the laboratory to industrialization,this work focuses on its supercapacitor application,and conducts a full-cycle industrial adaptability research from the perspective of raw materials,electrodes,and devices.At the raw material level,the phase purity of 1T Mo S₂ is a key feature that determines the electrode conductivity and energy storage performance.In order to achieve large-scale application,raw material preparations must have features such as high purity,scalability,and low cost.Currently,hydrothermal synthesis is the most scalable and cost-effective preparation strategy.However,the 1T phase purity of the product is low by hydrothermal methods,ranging from 25%to 70%.In order to achieve high-purity 1T Mo S₂ by hydrothermal synthesis,we propose a hydrothermal strategy based on the in-situ intercalation of hydrated lithium,revealing the mechanism of intercalation behavior on the generation and stability of Mo S₂ phase.As a result,the 1T phase purity of the prepared raw material reaches 82.7%.Thanks to the high phase purity and wide interlayer spacing,the volumetric capacitance(1054.5 F cm^-3)of the 1.45μm electrode is higher than 400～700 F cm^-3 of traditional Mo S₂ electrodes.At the electrode level,a large electrode thickness（50～100μm）is an important factor for high capacity of supercapacitors.In practical devices,the volume of passive components such as current collectors cannot be ignored,leading to a small volume proportion of thin electrodes and the poor capacity of the device.Therefore,designing high-performance 1T Mo S₂ electrodes with a large thickness has a practical value.But it faces dual challenges.Firstly,the self-assembly ability of material directly affects the thickness of the constructed electrodes.The poor self-assembly ability of1T Mo S₂ limits its electrode thickness within 1～24μm.Secondly,the volumetric capacitance of the electrodes will severely decay with increasing thickness,leading to a capacity decrease of the device.In this context,we propose a strategy to control the size of 1T Mo S₂ nanosheets,revealing the strengthening effect of small-sized nanosheets on the self-assembly ability of electrodes,and achieving a large thickness（62.3μm）of 1T Mo S₂ electrodes.At the same time,small-sized nanosheets significantly enhance the ion transport efficiency of the electrode,which overcomes the performance degradation caused by the increase in electrode thickness,and make its high volumetric capacitance(496.8 F cm^-3)comparable to the traditional 5μm Mo S₂ electrode.Finally,at the device level,based on the above research results,we took the lead in assembling 1T Mo S₂ supercapacitors with industrial grade（94.2μm×7 cm×70 cm）,and conducted device performance optimization and cost analysis.Its energy storage performance outperforms many commercial devices and new supercapacitors,and has the advantage of commercial-level cost.In summary,this work takes a practical perspective of 1T Mo S₂ and adopts full-cycle research for its industrialization.The research findings demonstrate practical guidance for large-scale applications,which help to promote the industrialization of other energy storage materials.