XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3293
potential of the particles. This process is not only about
restoring the performance of the degraded particles but also
about doing so in an energy-efficient manner. Energy effi-
ciency is crucial, as one of the main benefits of lithium-ion
batteries is their energy density. If the process of relithiation
consumes a significant amount of energy, it could negate
the energy-saving benefits of using these batteries.
Therefore, the goal of an energy-efficient relithiation
process is about striking a balance between restoring the
electrochemical performance of the degraded particles
while ensuring the process does not consume an excessive
amount of energy.
The current technologies applied in the relithiation of
spent LIBs are solid state sintering, electrochemical, ionic
liquids, eutectic salt and solution based relithiation.
Graphite Recovery
Graphite recovery process is a vital part of direct recycling.
This technique focuses on the recovery and upgrading of
the graphite anode material, which has been spent or uti-
lized in the functioning of electronic devices or EVs.
The graphite anode material plays a pivotal role in
lithium-ion batteries, where it serves as the host for lith-
ium ions during the discharge cycle. However, over time
and through repeated charging and discharging cycles, the
graphite material can deteriorate, resulting in degradation
of its capacity to deliver efficient performance.
The graphite recovery process aims to recover and
upcycle this spent graphite material, thereby extending its
usefulness and contributing to resource conservation. This
is achieved through a process of surface purification, which
is designed to rejuvenate the material and restore its perfor-
mance capabilities.
One of the distinguishing characteristics of this puri-
fication process is its selective nature. It is tailored in such
a way that it retains the beneficial components of the solid
electrolyte interface (SEI), which is a critical layer formed
on the surface of the graphite anode during the operation
of the battery (Adenusi et al., (2023)). The SEI layer plays a
crucial role in the stability and performance of the battery.
Therefore, its retention during the purification process is
of paramount importance. Approximately 78% of graphite
and 15% of cathode is recovered through the froth flota-
tion process. The SEI interface remains intact, without any
detrimental impact on any cathode or anode (Ruiting et
al., 2021). Conversely, the purification process also consid-
ers the removal of performance-inhibiting species from the
graphite material using thermal pyrolysis at 450°C for one
hour increasing the graphite purity to 98%.
These species accumulate over time and can impede
the performance of the material and reduce its effective-
ness. The selective removal of these species is therefore an
essential aspect of the purification process.
The graphite recovery process thus strikes a balance
between the retention of beneficial components and the
removal of performance-inhibiting species from the spent
graphite anode material. This balance ensures that the
recovered material is free of inhibiting species but also
enriched with its beneficial components, thereby ensuring
its optimal performance.
The improved life expectancy of the graphite anode
material can improve the efficiency of EVs and electronic
devices and contribute to the overall sustainability by
reducing the need for new raw materials and mitigating
electronic waste.
FUTURE DIRECTIONS
The following section discusses areas where recycling of bat-
teries looks to be moving with respect to newer processes
and products at a commercial scale.
Reuse Before Recycle
EOL EV batteries can be repurposed for BESS applications
in domestic and industrial applications. This can then defer
the true EOL of a LIB by a few years. Tankou et al., 2023
describe the reuse rather than recycle option as the ability
to identify and assess the LIBs that are suitable for repur-
posing. The key to repurposing the EV LIBs is to be able to
sort the different battery types prior to assessing them for
alternative use or EOL recycling.
Deep Eutectic Solvents
This is an exciting area that can lead to a more ecofriendly
use of solvents that have simpler process requirements yet
Figure 4. Steps to reusing an end of life electric vehicle battery
potential of the particles. This process is not only about
restoring the performance of the degraded particles but also
about doing so in an energy-efficient manner. Energy effi-
ciency is crucial, as one of the main benefits of lithium-ion
batteries is their energy density. If the process of relithiation
consumes a significant amount of energy, it could negate
the energy-saving benefits of using these batteries.
Therefore, the goal of an energy-efficient relithiation
process is about striking a balance between restoring the
electrochemical performance of the degraded particles
while ensuring the process does not consume an excessive
amount of energy.
The current technologies applied in the relithiation of
spent LIBs are solid state sintering, electrochemical, ionic
liquids, eutectic salt and solution based relithiation.
Graphite Recovery
Graphite recovery process is a vital part of direct recycling.
This technique focuses on the recovery and upgrading of
the graphite anode material, which has been spent or uti-
lized in the functioning of electronic devices or EVs.
The graphite anode material plays a pivotal role in
lithium-ion batteries, where it serves as the host for lith-
ium ions during the discharge cycle. However, over time
and through repeated charging and discharging cycles, the
graphite material can deteriorate, resulting in degradation
of its capacity to deliver efficient performance.
The graphite recovery process aims to recover and
upcycle this spent graphite material, thereby extending its
usefulness and contributing to resource conservation. This
is achieved through a process of surface purification, which
is designed to rejuvenate the material and restore its perfor-
mance capabilities.
One of the distinguishing characteristics of this puri-
fication process is its selective nature. It is tailored in such
a way that it retains the beneficial components of the solid
electrolyte interface (SEI), which is a critical layer formed
on the surface of the graphite anode during the operation
of the battery (Adenusi et al., (2023)). The SEI layer plays a
crucial role in the stability and performance of the battery.
Therefore, its retention during the purification process is
of paramount importance. Approximately 78% of graphite
and 15% of cathode is recovered through the froth flota-
tion process. The SEI interface remains intact, without any
detrimental impact on any cathode or anode (Ruiting et
al., 2021). Conversely, the purification process also consid-
ers the removal of performance-inhibiting species from the
graphite material using thermal pyrolysis at 450°C for one
hour increasing the graphite purity to 98%.
These species accumulate over time and can impede
the performance of the material and reduce its effective-
ness. The selective removal of these species is therefore an
essential aspect of the purification process.
The graphite recovery process thus strikes a balance
between the retention of beneficial components and the
removal of performance-inhibiting species from the spent
graphite anode material. This balance ensures that the
recovered material is free of inhibiting species but also
enriched with its beneficial components, thereby ensuring
its optimal performance.
The improved life expectancy of the graphite anode
material can improve the efficiency of EVs and electronic
devices and contribute to the overall sustainability by
reducing the need for new raw materials and mitigating
electronic waste.
FUTURE DIRECTIONS
The following section discusses areas where recycling of bat-
teries looks to be moving with respect to newer processes
and products at a commercial scale.
Reuse Before Recycle
EOL EV batteries can be repurposed for BESS applications
in domestic and industrial applications. This can then defer
the true EOL of a LIB by a few years. Tankou et al., 2023
describe the reuse rather than recycle option as the ability
to identify and assess the LIBs that are suitable for repur-
posing. The key to repurposing the EV LIBs is to be able to
sort the different battery types prior to assessing them for
alternative use or EOL recycling.
Deep Eutectic Solvents
This is an exciting area that can lead to a more ecofriendly
use of solvents that have simpler process requirements yet
Figure 4. Steps to reusing an end of life electric vehicle battery