novel electrode fabrication methods for lithium ion … of nofali project to develop safer, cheaper...
TRANSCRIPT
Copyright © Tekes
Novel Electrode Fabrication Methods for Lithium Ion Battery (NoFaLi)
Abstract:
Li-ion battery markets have been in a rapidly increasing mode since these
batteries overcame other techniques in portable applications; recently also
hybrid vehicles with larger Li-ion batteries were introduced. In Finland, we
have several companies with business fields related to Li-ion batteries from
mining and chemical synthesis to electrode and battery manufacturing and
recycling. In NoFaLi project we investigate and develop new environmentally-
friendly chemicals and methods for manufacturing Li-ion battery electrodes.
Moreover, outcomes of our preceding NoMaLi project are commercialized in
this joint project of Aalto University and University of Oulu in collaboration
with several Finnish enterprises.
Contact: Maarit Karppinen / [email protected]
GOALS OF NoFaLi PROJECT
To develop safer, cheaper and
environmentally-friendlier materials
and processes for Li-ion battery
(For large-scale applications)
Anode/cathode combination:
Li4Ti5O12 (LTO)/LiFePO4(LFP)
(Not yet used in commercial applications)
Several “work packages”:
(1) anode-side materials
(2) cathode-side materials
(3) binder materials
(4) fabrication techniques
(5) characterization
Commercialization of Sachtleben’s
LTO anode material (Hombitec LTO5;
200 nm) and a new water-based
printing process for Li-ion battery
manufacturing (Company funding:Sachtleben, Sunchemical
and Walki; Concultation: Tero Wallin, Tendon)
To increase battery know-how in
Finland (As long-term success in battery production in
Finland is NOT possible without basic battery
research at universities)
To learn from our very top-end
foreign collaborators
(By sending our PhD students to work in these
laboratories for long enough periods)
A! Aalto University
Department of Chemistry
First litium mine in
Europe
[LiAl(SiO3)2 spodumen]
Li-ion battery manufacturing
Li-ion battery material research
End-user of batteries
TiO2 & Li4Ti5O12
Battery chemicals
Battery recycling
Coating of electrodes
Inorganic Chemistry + Physical Chemistry
University
Consortium
Chydenius
Battery testing
INTERNATIONAL COLLABORATION
Prof. John B. Goodenough
University of Texas at Austin, USA
Prof. Yunhui Huang
Huazhong University of Science and
Technology, Wuhan, CHINA
Prof. Ryoji Kanno
Tokyo Inst. Technology, JAPAN
Dr. Peter Krtil
J. Heyrovsky Inst. Phys. Chem, CZECH
Prof. G. Lindberg
KTH – Royal Institute of Technology,
SWEDEN
Prof. B. Scrosati
University Rome Sapienza, ITALY
OUR CHOICES FOR ELECTRODE MATERIALS
Li1-xFePO4 CATHODE (pos. electrode)
Olivine structure (not layered)
Safe, cheap, environmentally benign
excellent for large-scale applications
Stable, constant voltage (3.4 V), excellent
cyclability, fast to charge
Problems: low electrical conductivity,
water-related stability issues
LiFePO4 LiCoO2 Li4Ti5O12
Li4+yTi5O12 ANODE (neg. electrode)
Spinel structure Li[Li1/6Ti5/6]2O4
No protective SEI (solid-electrolyte interface)
layer formed/needed safe
Stable, constant voltage (1.55 V), no
volume change, fast to charge
Problems: low electrical conductivity,
water-related stability issues
traditional
cathode
BATTERY TESTING LAB AT AALTO
1. Electrode Preparation
(LiFePO4 or Li4Ti5O12)
2. Coin-Cell Assembly
3. Electrical
Characterization
PILOT-SCALE BATTERY-TESTING LAB IN KOKKOLA:
• Built with public money (850 k€),
and in cooperation with Kokkola University Consortium Chydenius,
Technology Centre KETEK CENTRIA R&D, and the local industry
• Unique in Europe: comprehensive battery research lab in dry room of 40 m2
RESEARCH HIGHLIGHTS (so far)
Improved LFP cathode material through partial Mn-for-Fe substitution:
enhanced conductivity, higher cell voltage, more complete removal of trace
water
Optimization of electrodes made of Sachtleben’s LTO anode material (for the
composition and structure)
Development of a new water-based electrode manufacturing process for LTO
(using SunChemical’s Acryl S020 as a water-soluble binder)
First successful demonstration that the water-based process can be used with
pilot-scale gravure printing and slot-die coating methods
(Electrodes made with these techniques were shown to be stable at least
up to 500 charging/decharging cycles)
Initiation of a diploma thesis work to find out the best water-based large-scale
roll-to-roll coating method (with Walki)
Thermogravimetry (TG)
for in-situ water
absorption/desorption
studies
S. Räsänen, M. Lehtimäki, T. Aho,
K. Vuorilehto & M. Karppinen,
Solid State Ionics 211, 65 (2012).
0 1000 2000 300099.8
99.9
100.0
100.1
Time (min)
Rel
ativ
e m
ass
(%)
LiFePO4 Li(Fe,Mn)PO4
Li-ion battery deteriorates rapidly if water
gets into the sealed battery bag
All electrode materials absorb water from
surrounding humidity.
We have carried out detailed water
absorption/desorption studies using our
unique TG-humidity apparatus.
We have e.g. shown that LFP (LiFePO4)
cathode material can be stabilized against
water deteriation through partial Mn-for-Fe
substitution.
WATER-BASED BINDERS
in electrode manufacturing
[Presently: PVDF (polyvinyldifluoride) binder + NMP !!! (N-methylpyrrolidone) solvent]
Cheap
Non-toxic solvent
Environmentally friendly
Compatible with printing machine
Walki’s printing machine
NMP
Sachtleben: - electrode materials
SunChemical: - binder chemicals
Walki: - printing technology
EuropeanBatteries: - battery testing
E. Pohjalainen, S. Räsänen, M. Jokinen, K. Yliniemi,
D.A. Worsley, J. Kuusivaara, J. Juurikivi, R. Ekqvist,
T. Kallio & M. Karppinen,
Journal of Power Sources 226, 134 (2013).