Advances in Lithium Ion Anodes and Inactive Materials
Inactive materials have a significant impact on cell cost, performance, life, and reliability. LLIBTA Session 2 reviewed inactive components that contribute to electrode integrity and cell performance, and explored recent advances in material processing.
Session Chairman:
Philippe Blanchard, Product Engineering Manager, Saft Automotive Batteries
Dr. Philippe Blanchard received his PhD in Electrochemistry in 1984 (Research area for PhD: corrosion of construction steel in sea water). Dr. Blanchard joined Saft in 1985. He has taken the following positions: Research engineer in the area of Ni-Cd batteries, Research Group Leader for Ni-MH batteries, Cell Engineering Manager for industrial li-ion cells. He has been the program manager for several USABC and European programs. He joined the JV with Johnson Controls in 2006 with HEV cell design responsibility. Since 2011 and the termination of the JV, he still keeps the same responsibility within the SAFT Automotive Battery Group.
SESSION AGENDA
Tailor-made Carbon and Graphite-based Anode Materials for Lithium-Ion Batteries Dr. Ivano Galbiati, Project Manager, SGL Carbon GmbH
Abstract
Since the first commercial application of insertion anodes, the superiority of lithium ion batteries is strongly connected to the use of carbon based materials. In contrast to many chemically different lithium based cathode materials, the anode is dominated mainly by artificial and natural graphite with hard and soft carbon playing a minor role. The amount and type of sites able to reversible lithium accommodation depend in a complex manner on the crystalline structure, the particle size, shape, and distribution. Additionally, interaction with the electrolyte is influenced by the surface modification such as a carbon coating. All these parameters together affect the anode performance regarding capacity, efficiency, lifetime, charging behavior and safety. The topics that will be covered by this presentation outline how graphite and carbon based anodes are not just black powders but tailor made engineered materials:
Anode materials overview
Material synthesis and modification
Soft and hard carbons
Graphite
New generation anodes: carbon/graphite composites
On the whole, for the last 20 years carbon and graphite have been the anode material of choice and will play also a major role in the upcoming years.
Close Abstract
The Development of Non-graphitizable Carbon “CARBOTRON® P” for Automotive Lithium-Ion Batteries Hiroshi Imoto, Chief Researcher, Advanced Battery Materials Research Department, Kureha Corporation
Abstract
Kureha Corporation developed CARBOTRON® for world-first commercialized Lithium-ion batteries (LIBs) released by SONY in 1991. Properties required for Automotive LIBs are different from that required for Portable electronics LIBs. Kureha has in-depth technology in controlling and designing carbon structure, and is bringing it to automotive applications.
Outline
Company introduction
Kureha Corporation
Kureha Battery Materials Japan Co., Ltd.
Introduction
Our LIBs business history
Our products (CARBOTRON®, KF POLYMER®)
CARBOTRON® with unique structure
The classification by the difference in carbon structure
Fundamental properties of anode materials
Li storage mechanism in CARBOTRON® (Li cluster Model)
Electrochemical Properties of non-graphitizable Carbon
Charge / Discharge properties
Low temperature properties
Durability / Cycle properties
Application / Track record
Development plan
Summary
Close Abstract
3M - Battery Materials for Mobility Dr. Egbert Figgemeier, Application Development Specialist, Electronics Market Materials Division, Battery Materials, 3M Center
Abstract
Alloy-based negative electrodes have been considered the “next-generation negative electrode” expected to replace graphite for many years. However, few exist in the marketplace. Manufacturing alloy-based cells with acceptable cycling poses a major challenge, indeed many components of the cell must be adapted in order to obtain successful cycling.
Two main strategies have emerged for alloys. The active/inactive approach where the alloy is usually in the form of micron sized particles and the “nano” approach where the (usually) pure active metal is on the nanometer length scale (nanoparticle, nanowire, nanorod etc…).
3M has a long history of alloy research focusing on active/inactive alloys and has developed scalable and commercially viable Si-based alloys. This presentation will focus on recent advances in the implementation of active/inactive alloys in commercially viable electrodes as well as the use of high precision techniques to diagnose failure mechanisms.
The combination of high precision coulometry with isothermal micro-calorimetry allows the identification of parasitic reactions and failure mechanisms in Li-ion coincells. These techniques are used to study composite graphite/alloy electrodes having equivalent volumetric capacities and containing either active/inactive alloys or Si nanoparticles. The failure mechanisms and parasitic reactions are discussed. Si nanoparticles are found to have problematic levels of parasitic reactions.
Close Abstract
Design, Synthesis and Characterization of Li-Alloying Anode Materials Prof. Nae-Lih Nick Wu, Professor, National Taiwan University
Abstract
Application of Li-alloy anode faces two critical challenges. The first challenge involves serious volumetric expansion and contraction taking place during lithiation/delithiation, which causes mechanical failure of the electrode, leading to rapid capacity fading. The second critical challenge is SEI formation. For Si, as well as other high-capacity anodes, excessive SEI formation causes not only depletion of electrolyte but also considerable electrode expansion, which eventually leads to mechanical failure of the electrode. This presentation looks at some measures that have been taken to overcome these issues and showing promising outcomes.
Capacity issue:
Introducing pre-set voids within either the active material particles or the electrode layer to accommodate cyclic volumetric variations has been a common practice for enhancing cycle stability of Si-based anodes.
The alloy anode is often combined with highly porous C to give composite anodes showing significantly enhanced cycling stability.
The presence of the porosity and the use of the light-weight supporting component (carbon) may lead to serious reduction of electrode capacity density
The inter-relation between the pre-set porosity and the constituents of the composite anode will be discussed to elucidate the microstructure design from the viewpoint of capacity density.
Comparison in performance will be give among various Si-C and Si-metal composite electrodes.
SEI issue:
Excess SEI formation occurs in alloy anode, resulting in electrode expansion.
Evidence given to show that surface chemistry of the alloying anode has strong effects on SEI formation
Chemical nature of the binder also show strong effects
Close Abstract
Pre-Lithiated Technology Status and Prospects Dr. Yangxing Li, Asia Energy Technology Manager, FMC Lithium
Abstract
Public concerns over finite fossil-fuel resources over increased population on the earth and global warming related to CO2 emissions have demand that society develop sustainable and renewable/”green” energy devices. Due to its high energy density, good cycle life and many other good characteristic performances, lithium-ion batteries (LIBs) technology looks imperative among all the rechargeable battery chemistries to help society reach this goal. LIBs are positioned to possibly take over the electric vehicle market and help to speed the growth of this sector. Even though the energy density for lithium-ion battery has significantly improved since LIB was introduced in 1990 by Sony, intensive worldwide efforts have continued working on this to make battery offer improved energy.
High-energy battery demands novel active electrode materials, which has required much more electrochemically active lithium atoms. One promising is to introduce lithium-alloy-reaction-based Si composites to replace lithium-intercalation-based carbon, which by nature have large first-cycle irreversible capacity. Sometimes, the capacity loss can be significant-- as high as 1000 mAh/g, which is much higher than the capacity that the current cathode materials can offer, e.g. LiCoO2 160 mAh/g, LiMn2O4 120 mAh/g, LiFePO4 150 mAh/g, or LiNi0.8Co0.15Al0.05O2 180 mAh/g.
Prelithiation technologies are effectively to address the 1st cycle inefficiency as well as are able to pave new avenue to more choices for novel active materials. Several technologies have been proposed to address this irreversible capacity in the first cycle, including:
Excess cathode material loading;
Lithium-rich cathode;
High concentration lithium salt;
“Sacrificial salts”;
Organometallic lithium
Thin lithium foil;
and Stabilized Lithium Metal Powder (SLMP®).
SLMP is a pioneering and revolutionary material and technology developed by FMC that can effectively compensate the irreversible capacity, increase the energy density, as well as open up more choices for anode and cathode materials to meet today and future market demands. In this presentation, we will briefly summarized pre-lithiated technologies and will discuss in detail the performances improvement by SLMP. Such improvement can be offered to various energy storage devices: not only lithium-ion batteries but also lithium-ion supercapacitors. Due to the coating homogeneity, SLMP is given as a non-pyrophoric lithium metal powder that can be safely handled in the dry room. Today SLMP has become the most attractive and important prelithiation technology.
Close Abstract
Relationship between Mixing Processes, Slurry Dispersion Properties, and Electrode Performance Tsumoru Ohata, Technical Director, PEACE Battery Device Department, PRIMIX Corporation
Abstract
When the lithium-ion battery was first developed, PRIMIX was the first manufacturer to supply mixers for electrode slurry manufacturing. The batch mixing method used then is still being used today in mass production and R&D. In recent years, PRIMIX has developed and implemented a continuous dispersion process to meet the production needs of the automotive battery industry.
Electrodes are made by coating a mixture of electrode materials known as electrode slurry. It is well known among engineers that the performance of an electrode not only depend on the materials used, but also the state of the dispersed particles or dispersion properties.
Technical documentation and research on electrode slurry mixing technology is scarce, and the current “black box” state of this process has been an outstanding issue. The source of this issue is the nature of the batch mixing process requiring the build-up of experience and a highly skilled worker.
This presentation will outline a new continuous dispersion process and present the results of mixing various electrode materials with a focus on the state of dispersed conductive agent throughout the electrode slurry and the resulting electrode properties.
Characteristics of the continuous dispersion process.
Challenges of the batch mixing process.
The high speed thin-film mixer, the core of the continuous dispersion process.
Relationship between the state of dispersion of conductive agent and electrode performance.
Control of the formation of carbon structures, and its relation to electrode performance.
Improvements over the conventional batch mixing process.
Possible effects on the dispersion of the latest electrode-related materials.
Size reduction of the production facility due to the continuous dispersion process.
Close Abstract
Development of Water-borne Slurry with Nano-sized Ceramic Particles for Functional Layer Dr. Kai Kremer, Automotive Marketing & Technical Service Representative, Zeon Europe GmbH
Abstract
Lithium-ion battery (LIB) has been used as a high density storage device for a variety kind of applications ranging from portable electronics to electric vehicles. Today, especially in vehicle application, the layer of nano-sized ceramic particles, often called heat resistant layer, coated on the polyolefin separator or electrode in order to reduce the risk of runway reaction and improve battery performances. In order to form the ceramic layer, organic solvent, N-methylpyrrolidone (NMP) is typically used. However, the organic solvent like NMP has several drawbacks. First, it is said to have teratogenicity. Second, there are cost issues which include not only the material cost itself but also solvent recovery equipment and explosion-proof facility. ZEON has been challenging to change the solvent from organic one to water, and launched a lot of water-based products including negative and positive binders since 1995. Now ZEON has developed water-borne slurry with nano-sized ceramic particles, which can be utilized on both electrode and polyolefin separators. In the presentation, we indicate several LIB performances with heat resistant layer on either separator or electrode, including the function of short circuit avoidance, rate property, cycle performance and storage performance at high temperature, and also discuss the mechanism of the improvement in the storage performance test, which suggest the protective function of the active material in the electrode.
