The authors of this paper include Cheng Li, Yuqi Wu, Fucheng Ren, Jun Liu, Ying Lin, Meng Xia, Huanran Wang, Chunyan Meng, Zhenyu Wang, and Zhengliang Gong. They are affiliated with Xiamen University, South China University of Technology, Shaanxi University of Science & Technology, and Guilin Electric Appliance Research Institute Co., Ltd., and their research focuses on the fields of silicon-based integrated optoelectronic materials and devices, novel semiconductor low-dimensional materials and devices, solid-state batteries, electrolyte materials, and electrochemical properties.

1. Introduction

• Advantages and application prospects of All-Solid-State Batteries (ASSB)
• The potential and challenges of silicon as an anode material in ASSB
• Prelithiation technology and its application in silicon-based anodes
• Objectives and significance of this study

2. Results and Discussion

• Preparation process of prelithiated silicon-based composite anode (c-Li1Si)
• Structural characterization of c-Li1Si
• XRD analysis
• SEM images and particle size distribution
• XPS analysis
• ssNMR analysis
• Electrochemical performance of c-Li1Si
• Structural characterization of c-Li1Si at different Li1Si/LPSCl ratios
• Electronic and ionic conductivity
• Cycling performance
• Pressure measurement
• Structural stability
• Comparative electrochemical performance of c-Li1Si-60 and p-Li1Si
• Half-cell performance
• ASSB performance
• Cycling stability
• Symmetric cell performance
• Influence of N/P ratio
• Interface stability and electrochemical impedance analysis
• XPS analysis
• EIS analysis
• Mechanical properties and volume changes
• Pressure changes
• Thickness changes
• Structural stability
• Structural reversibility

3. Conclusion

• Advantages of c-Li1Si anode
• Application prospects of c-Li1Si anode in ASSB

4. Experimental Section

• Materials
• Preparation
• Battery assembly
• Material characterization
• Electrochemical tests

Q: What specific research methods were used in the paper?

• Material Synthesis: Dry mixing method combined with heat treatment to prepare pre-lithiated Li1Si material, and mixed with LPSCl solid-state electrolyte to prepare composite anodes.
• Battery Assembly: Homemade model batteries, using NCM811 cathode and composite anodes with different proportions of Li1Si/LPSCl to assemble all-solid-state batteries.
• Material Characterization:
  • Scanning Electron Microscope (SEM) to observe the morphology and microstructure of the material.
  • Laser particle size analyzer to test the particle size distribution of the material.
  • X-ray Diffraction (XRD) to analyze the crystal structure of the material.
  • X-ray Photoelectron Spectroscopy (XPS) to analyze the surface chemical composition of the material.
  • Solid-state 7Li Nuclear Magnetic Resonance (ssNMR) to analyze the chemical state of Li1Si material.
  • X-ray Computed Tomography (X-ray CT) to analyze the three-dimensional microstructure of the electrode, and calculate the tortuosity and porosity.
• Electrochemical Testing:
  • Electrochemical Impedance Spectroscopy (EIS) to study the interfacial impedance and ionic diffusion impedance of the battery.
  • AC impedance test to measure the electronic and ionic conductivity of the electrode.
  • Constant current charge-discharge test to evaluate the capacity, rate performance, and cycling stability of the battery.
  • Symmetric cell test to study the interfacial stability of the battery.
• Mechanical Testing:
  • Pressure sensor to measure the pressure changes of the battery during cycling.
  • Precision pressure and displacement sensors to measure the expansion behavior of the battery during cycling.
  • Homemade battery device combined with force sensor to measure the mechanical stress changes of the battery during cycling.

Q: What are the main research findings and achievements?

• The pre-lithiated Li1Si composite anode (c-Li1Si) has a dense structure, effectively improving the reaction kinetics and mitigating volume expansion during cycling.
• The c-Li1Si-60 anode exhibits excellent electrochemical performance, including superior rate performance and 84.4% capacity retention after 1000 cycles.
• The c-Li1Si-60 anode shows excellent performance even at a low N/P ratio (1.68).
• The introduction of LPSCl solid-state electrolyte effectively mitigated the volume changes of the Si anode and maintained the integrity of the electrode structure.
• The c-Li1Si anode formed a stable passivation layer during cycling, inhibiting side reactions and improving the stability of the electrode.

Q: What are the current limitations of this research?

• The performance of the c-Li1Si anode at a low N/P ratio still needs to be further improved.
• Further research is needed on the stability of the c-Li1Si anode during long-term cycling.
• It is necessary to explore more effective pre-lithiation methods to optimize the depth of pre-lithiation and the structure of the composite electrode.