First 18 months

Primary goals of Hi-C:

• Understand the important interfaces in an operating battery on an atomic and molecular scale.
• Characterize the formation and nature of interfaces in situ.      
• Devise methods to control and design interface formation, stability and properties.  
• Prepare ion-conducting membranes, mimetic of the polymeric part of the SEI, in order to study their mechanical and electrochemical properties. 

The Hi-C consortium addresses the scientific challenges that are limiting power density, storage capacity, safety, lifetime and state of health of electrochemical storage devices such as lithium-ion batteries, conversion batteries and supercapacitors.

A number of advanced experimental and computational methods will be developed and applied to well-known battery chemistries such as LiFePO₄ and Li(Ni_1/3Mn_1/3Co_1/3)O₂ vs. graphite electrode materials used in lithium-ion batteries. The results will be used for increasing the stability of silicon as negative electrode material and of positive electrode materials such as LiFeBO₃ and LiVO₂F. In operando cell monitoring will be developed for batteries and supercapacitors.

Achievements: During the first 18 months of the Hi-C project the focus has been on developing the tools and methods for the project. 

• Materials specification, selection, preparation, characterization and distribution to partners. 
• Developing processes for preparation of silicon nanowires.      
• Synthesis method for high-performance LiFeBO₃.      
• Synthesis and characterization of LiVO₂F as a new cathode material.  
• High resolution synchrotron powder diffraction characterization of LiFeBO₃ and LiFePO₄.  
• Development of capillary-based in situ battery cells for in situ studies.      
• In situ high resolution powder diffraction studies of LFP and LFB batteries. 
• In situ diffraction studies of conversion batteries.      
• TEM and EELS studies of partially delithiated LFP samples.  
• TERS (Tip enhanced Raman spectroscopy) instrument installed.  
• SECM (Scanning electrochemical microscopy).      
• Targeted SEI formation by additives and characterization by XPS.      
• Formation of SEI mimetic membranes.      
• Sensor monitoring strategy and set-up for in operando monitoring.  
• Testing heat flux sensors for in operando monitoring.      
• Computational study of overpotentials across interfaces in LiFeBO₃.  
• 1-Dimensional FEM (Finite element method) models for supercapacitor and SEI developed.  
• DFT calculations of ionic transport, pathways and barriers in Li_xBO₃.      
• Fabrication and charge/discharge tests of NMC/C-based coin cells.  
• Studies of additive effect by gas analysis using NMC/C pouch cells.  
• Development of a sealed cell for in situ SECM. 

See the newsletter for more detailed results. 

Disseminations

One patent, three journal papers, one book chapter, 11 posters and 22 presentations.