The formation of the solid electrolyte interphase during the formation and conditioning steps, is a very time consuming and expensive process. We present an active formation method in LiNi1/3Mn1/3Co1/3O2 (NMC-111) versus graphite lithium-ion batteries, which maintains the cycling performance of the cells. Ten different active formation protocols were evaluated, which consisted of cycling between an upper (Vu) and lower (Vl) voltages. The cells were evaluated using electrochemical impedance spectroscopy (EIS) and cycling. X-ray photoelectron spectroscopy was used to analyse the surface of the electrodes after cycling. Cycling performance and resistance measurements from the EIS results confirm the different effect of formation protocols in the lifetime and performance of the cells. We show that during the formation protocol the interface composition is optimised through the transport of lithium ions through the initial organic decomposition layer on the graphite at higher cell voltages (>3.65 V). These higher voltage cycling formation protocols giving an interface with greater stability and enhanced cycling are observed in the cells.
Focus on Fundamental Properties of Interfaces in Energy Conversion and Storage
Guest Editors
John Irvine, University of St Andrews, UK Job Thijssen, University of Edinburgh, UK Jon Binner, University of Birmingham, UK Steve Parker, University Of Bath, UKScope
The interface between active components and, indeed, the surface are usually of great importance in determining the functionality of any energy materials application. For example, the critical region determining the performance and lifetime of most electrochemical systems is normally at the electrode side of the electrode/electrolyte interface. Typically this electrochemically active region only extends a few microns and for best performance involves intricate structures and nanocomposites. Much of the most exciting recent energy research involves understanding processes occurring at this interface and in developing new means of controlling the structure at the nanoscale.
This focus collection builds upon a workshop organised under the Multiscale Tuning of Interfaces and Surfaces for Energy Applications Network (UK) and seeks to extend our understanding of the key aspects relating to interfaces in materials for energy conversion and storage. We warmly welcome research papers and topical reviews addressing this understanding covering topics such as:
- Control of defect and interface chemistry for improved energy materials
- Modelling atomistic processes at interfaces and surfaces
- Structure and stability of interfaces
- Modelling transport along and across interfaces
- Creating continuous composite structures using phase transitions and flow
- Materials processing/engineering of ceramic interfaces
Topical Review
Papers
The formation of the solid electrolyte interphase during the formation and conditioning steps, is a very time consuming and expensive process. We present an active formation method in LiNi1/3Mn1/3Co1/3O2 (NMC-111) versus graphite lithium-ion batteries, which maintains the cycling performance of the cells. Ten different active formation protocols were evaluated, which consisted of cycling between an upper (Vu) and lower (Vl) voltages. The cells were evaluated using electrochemical impedance spectroscopy (EIS) and cycling. X-ray photoelectron spectroscopy was used to analyse the surface of the electrodes after cycling. Cycling performance and resistance measurements from the EIS results confirm the different effect of formation protocols in the lifetime and performance of the cells. We show that during the formation protocol the interface composition is optimised through the transport of lithium ions through the initial organic decomposition layer on the graphite at higher cell voltages (>3.65 V). These higher voltage cycling formation protocols giving an interface with greater stability and enhanced cycling are observed in the cells.