Carbon binder domain networks and electrical conductivity in lithium-ion battery electrodes: A critical review. (September 2022)

• Record Type: Journal Article
• Authors: Entwistle, Jake; Ge, Ruihuan; Pardikar, Kunal; Smith, Rachel; Cumming, Denis
• Is Part Of: Renewable & sustainable energy reviews. Volume 166(2022)
• Publication Date: 2022-09
• Subjects: Lithium-ion battery -- Battery electrode -- Electrical conductivity -- Conductive additive -- Battery manufacture -- High performance battery; LIB Lithium-ion battery -- CA Conductive Additive -- CBD Carbon Binder Domain -- SEI Solid Electrolyte Interphase -- NMC Nickle Manganese Cobalt Oxide -- PVDF Polyvinylidene fluoride -- SEM Scanning Electron Microscopy -- TEM Transmission Electron Microscopy -- FIB Focused Ion Beam -- xCT X-ray Computed Tomography -- MIP Mercury Intrusion Porosimetry -- EIS Electrochemical Impedance Spectroscopy -- EC Equivalent Circuit -- PITT Potentiostatic Intermittent Titration Technique -- GITT Galvanostatic Intermittent Titration Technique -- DEM Discrete Element Method -- FEA Finite element analysis -- MD Molecular Dynamics -- CFD Computational Fluid Dynamic -- PBM Population Balance Modelling -- RN Resistor Network; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2022.112624
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: In a drive to increase Li-ion battery energy density, as well as support faster charge discharge speeds, electronic conductivity networks require increasingly efficient transport pathways whilst using ever decreasing proportions of conductive additive. Comprehensive understanding of the complexities of electronic conduction in lithium-ion battery electrodes is lacking in the literature. In this work we show higher electronic conductivities do not necessarily lead to higher capacities at high C-rates due to the complex interrelation between the electronically conducting carbon binder domain (CBD) and the ionic diffusion within electrodes. A wide body of literature is reviewed, encompassing the current maxims of percolation theory and conductive additives as well as the relationships between processing steps at each stage of electrode manufacturing and formation of electronic conduction pathways. The state-of-the-art in electrode characterisation techniques are reviewed in the context of providing a holistic and accurate understanding of electronic conductivity. Literature regarding the simulation of electrode structures and their electronic properties is also reviewed. This review presents the first comprehensive survey of the formation of electronic conductivity networks throughout the CBD in battery electrodes, and demonstrates a lack of understanding regarding the most optimum arrangement of the CBD in the literature. This is further explored in relation to the long-range and short-range electrical contacts within a battery electrode which represent the micron level percolation network and the submicron connection of CBD to active material respectively. A guide to future investigations into CBD including specific characterisation experiments and simulation approaches is suggested. We conclude with suggestions on reporting important metrics such as robust electrical characterisation and the provision of metrics to allow comparison between studies such as aerial current density. Future advances in characterisation, simulation and experimentation will be able to provide a more complete understanding if research can be quantitatively compared. Highlights: Critical parameters for the structure of the CBD are missing in the literature. More fundamental insights are needed to help guide design of electrodes, particularly as they become thicker. Advances in characterisation techniques are needed to in determining, structure, mechanical and electronic properties of CBD. New approaches for processing CBD will be required for novel processing routes such and dry and semi-solid. Advances in CBD modelling are needed to support advanced electrode design and processing.