3266
Mechanical Recycling of Complex Structures of Energy Materials
Carlo Kaiser, Malena Staudacher, Alexandra Kaas, Christian Wilke, Anna Thielen, Tony Lyon, Konstantin
Dahl, Urs A. Peuker
Institute of Mechanical Process Engineering and Mineral Processing,
Technische Universität Bergakademie Freiberg, Germany
ABSTRACT: Modern energy materials in batteries, fuel cells, electrolyzers and electronic components contain
several critical and valuable raw materials. Their inner structure has typical length scales in the 10–100 µm
range, which is similar to finely intergrown geogenic raw materials, ores respectively. The mechanical recycling
of the end-of-life energy materials therefore requires a higher attention and effort compared to conventional
recycling and becomes as challenging as mineral processing of fine-grained ores. The contribution uses the
examples of lithium ion batteries (LIB), high-temperature (HT) and polymer electrolyte membrane (PEM)
electrolyzers and gives an overview on different technological approaches in the mechanical processing of these
materials and allows a technological transfer from primary to secondary raw materials processing.
INTRODUCTION
Technical facilities for sustainable energy infrastructure that
are to be set up as part of the energy transition, i.e., the
decarbonization of the energy infrastructure, use a broad
raw material base for their functionality. It is known that
these facilities (batteries, solar panels, fuel cells and elec-
trolyzers) contain a large number and large quantity of
so-called critical raw materials. The criticality of the raw
materials results from their availability on the market and
the general market situation with regard to competition
between suppliers. It is therefore a key economic issue to
make intensive use of these critical raw materials in a circu-
lar economy.
The necessary technologies are required for such
a circular economy that makes secondary raw materi-
als available. As the establishment of a sustainable energy
infrastructure represents new technological structures, the
associated recycling processes have not yet reached the tech-
nological maturity, the necessary technological readiness
level (TRL). It is therefore an important task of scientific
and technological development to investigate and quantify
such recycling technologies and ultimately bring them to
market.
What is special about the structures and facilities of sus-
tainable energy infrastructure is their characteristic length
scale. In batteries, fuel cells and electrolyzers as well as in
solar panels, thin layers of different materials are brought
together to achieve the respective functionality. The char-
acteristic length in such a structure is sometimes less than
10 µm, for example copper foils in batteries or functional
iridium-containing catalyst layers in polymer-electrolyte-
membrane (PEM) electrolyzers. Mechanical recycling, i.e.,
the mechanical processing of these secondary raw materi-
als, therefore has to deal with very finely intergrown struc-
tures when viewed from the perspective of the primary
raw materials. In addition, the variety of materials in these
technological components and facilities is higher than in
an ore deposit, which can pose a challenge for mechanical
separation processes. Another aspect to consider with sec-
ondary raw materials is that as they are complex composite
Mechanical Recycling of Complex Structures of Energy Materials
Carlo Kaiser, Malena Staudacher, Alexandra Kaas, Christian Wilke, Anna Thielen, Tony Lyon, Konstantin
Dahl, Urs A. Peuker
Institute of Mechanical Process Engineering and Mineral Processing,
Technische Universität Bergakademie Freiberg, Germany
ABSTRACT: Modern energy materials in batteries, fuel cells, electrolyzers and electronic components contain
several critical and valuable raw materials. Their inner structure has typical length scales in the 10–100 µm
range, which is similar to finely intergrown geogenic raw materials, ores respectively. The mechanical recycling
of the end-of-life energy materials therefore requires a higher attention and effort compared to conventional
recycling and becomes as challenging as mineral processing of fine-grained ores. The contribution uses the
examples of lithium ion batteries (LIB), high-temperature (HT) and polymer electrolyte membrane (PEM)
electrolyzers and gives an overview on different technological approaches in the mechanical processing of these
materials and allows a technological transfer from primary to secondary raw materials processing.
INTRODUCTION
Technical facilities for sustainable energy infrastructure that
are to be set up as part of the energy transition, i.e., the
decarbonization of the energy infrastructure, use a broad
raw material base for their functionality. It is known that
these facilities (batteries, solar panels, fuel cells and elec-
trolyzers) contain a large number and large quantity of
so-called critical raw materials. The criticality of the raw
materials results from their availability on the market and
the general market situation with regard to competition
between suppliers. It is therefore a key economic issue to
make intensive use of these critical raw materials in a circu-
lar economy.
The necessary technologies are required for such
a circular economy that makes secondary raw materi-
als available. As the establishment of a sustainable energy
infrastructure represents new technological structures, the
associated recycling processes have not yet reached the tech-
nological maturity, the necessary technological readiness
level (TRL). It is therefore an important task of scientific
and technological development to investigate and quantify
such recycling technologies and ultimately bring them to
market.
What is special about the structures and facilities of sus-
tainable energy infrastructure is their characteristic length
scale. In batteries, fuel cells and electrolyzers as well as in
solar panels, thin layers of different materials are brought
together to achieve the respective functionality. The char-
acteristic length in such a structure is sometimes less than
10 µm, for example copper foils in batteries or functional
iridium-containing catalyst layers in polymer-electrolyte-
membrane (PEM) electrolyzers. Mechanical recycling, i.e.,
the mechanical processing of these secondary raw materi-
als, therefore has to deal with very finely intergrown struc-
tures when viewed from the perspective of the primary
raw materials. In addition, the variety of materials in these
technological components and facilities is higher than in
an ore deposit, which can pose a challenge for mechanical
separation processes. Another aspect to consider with sec-
ondary raw materials is that as they are complex composite