Scientific publication

Interface evolution and performance degradation in LiCoO2 composite battery electrodes monitored by advanced EQCM

Authors: Wanli Gao, Christel Laberty-Robert, Natacha Krins, Catherine Debiemme-Chouvya, Hubert Perrot and Ozlem Sel.
Journal: Electrochimica Acta (2022)

 

Abstract

Unravelling the underlying reasons for degradation mechanism of battery materials is of great fundamental and practical importance. For a classical electrode consisting of an active material, a conductive additive, and a polymeric binder, its capacity fading is commonly related with (i) mechanical degradation of polymeric binder and/or (ii) structural and compositional degradation of active materials. The former is more relevant for electrodes showing volume expansion and represented by the progressive breakage of polymeric binder network during battery operation, leading to the dissolution of the other two components into electrolytes. The latter is generally reflected by an irreversible phase transition in active materials, which may affect the species exchanged at the electrode/electrolyte interface and their interfacial transfer dynamics. By employing a coupled methodology pairing electrochemical techniques with piezoelectric probes derived from quartz crystal microbalance (QCM), this work reports on the evolution of the interfacial processes during electrochemical cycling and correlates to the performance degradation of the electrodes. Shown on a LiCoO2 (LCO) composite electrode as a model system, it was revealed that bare Li+ without a hydration sheath plays a dominant role in charge balance irrespective of the aging degree of the electrode under the experimental conditions of this work. However, Li+ transfer is closely accompanied with free H2O molecules with a Li+:H2O ratio around 10:1 at a polarization state close to LCO redox potential (0.65 V vs. Ag/AgCl). This ratio persists in all cycled electrodes with gradually faded interfacial transfer kinetics of Li+ and H2O along cycling. Such a fading in species interfacial transfer kinetics driven by the surficial evolution from LiCoO2 to CoO plays a major role in the electrode performance degradation during cycling.

LiCoO2 composite battery electrodes

You may read the full paper here.

The difference the “D” makes in QCMD

AWSensors presents a new Technology Note on the importance of dissipation measuring when working with QCMD: “The difference the “D” makes in QCMD”.

Dissipation

What is dissipation, and why it is useful?

Quartz Crystal Microbalance with Dissipation, or QCMD, is having a tremendous impact on research in the soft and biological interfaces fields because of its versatility and the wealth of information it provides. In this Technology Note, we discuss the origins of dissipation in the different systems studied by QCMD, from complex fluids and polymer films to biomolecular and particle assemblies, and the information dissipation can provide, from characterizing viscoelasticity to studying molecular conformation.

In this Technical Note we discuss the origins of dissipation, how it can be used to verify the applicability of the Sauerbrey relationship and their interaction with the viscoelasticity and in the biological sensing.

 


Download Full Technology Note

You can read and download the full Technology Note in pdf file from this link or download it from our Technology Web Page where you can find this and the rest of our Technology and Application Notes.

 

 

Publication on AWSensors technology

Synthesis and covalent immobilization of redox-active metallopolymers for organic phase electrochemistry

Authors: Hanna Hübner, Riccardo Candeago, Deborah Schmitt, Alexander Schießer, Beichen Xiong, Markus Gallei, Xiao Su.

Journal: Polymer, 2022.