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 / maarit.karppinen@aalto.fi

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).