1
24-061
Minimizing Leaching of Al, Co, Cu, Fe, Li, and Ni
During Discharge of Lithium-Ion Batteries
L. A. Sanchez-Calderon
Missouri Univ. of Science and Tech., Rolla, MO
L. Alagha
Missouri Univ. of Science and Tech., Rolla, MO
ABSTRACT
The existing methods for recycling lithium-ion batter-
ies present initial hurdles related to the safe handling and
preparation of the batteries to avert potential explosions.
Submerging batteries in sodium chloride (NaCl) solution
has become an acceptable industrial practice. However, the
use of NaCl to discharge lithium-ion batteries rusts the bat-
teries’ cases and releases metals which impacts the down-
stream processes that involve selective recovery of Li. This
study aimed to determine the optimal concentrations and
pH range of NaCl for the discharge of lithium-ion batteries
for the purpose of minimizing the leach of Al, Co, Cu, Fe,
Li, and Ni.
INTRODUCTION
Lithium-ion batteries contain valuable metals like cobalt,
copper, lithium, and nickel making its recycling economi-
cally very attractive (Ojanen et al., 2018). Recycling these
metals also helps mitigate social and environmental impacts
associated with mining practices of cobalt and lithium
(Banza et al., 2009 Liu &Agusdinata, 2020). There are
two main practices currently adopted by industry to recy-
cle lithium-ion batteries. The first is the pyrometallurgy
approach which consumes high energy and requires a high
initial investment (Zhou et al., 2021). The second is the
hydrometallurgical processing which requires discharging
prior to leaching to avoid potential explosions (Liang et
al., 2021). The discharge reaction is shown in Equation 1
(Bartholome et al., n.d.):
LiC6 +CoO2 → C6 +LiCoO2 (1)
Lithium oxide is still reactive with water, but the reac-
tion occurs at a slower rate than lithium metal with water.
There are primarily two methods for discharging a Li
battery. The first involves connecting the battery to an elec-
tric circuit, which preserves the battery’s shape and other
conditions but is not practical for industrial- scale opera-
tions. The second method entails immersing the battery
in an aqueous solution containing an electrolyte, typically
NaCl. In the latter scenario, the NaCl solution serves as
a conductive medium by facilitating the flow of electrons.
The primary concern with the discharge processes with
NaCl, or other media, is the corrosion of the battery casing
and the release of metals. (Bae &Kim, 2021). The release
of metals is undesirable as they can react with water, gen-
erating heat in the process. Moreover, the loss of valuable
metals during the discharge process is economically unfa-
vorable. Ultimately, it results in increased costs associated
with treating the waste solutions to minimize environmen-
tal impacts. (Li et al., 2010).
To control the release of metals (i.e., Al, Co, Cu, Fe,
Li, and Ni), this study proposed a 2-step procedure. The
first step involved varying the concentration of NaCl in the
submerging solution and studying its impact on battery
case’s corrosion rate at neutral pH. This aimed to select the
optimal concentration at which the corrosion is minimal.
In the second step, adjustments were made to the other key
parameter, namely, pH. The pH is a critical factor as indi-
cated by the Pourbaix diagram shown in Figure 1 (Barnes,
2014). The real challenge associated with this approach was
to attain the maximum time limit of 16 hours, designed to
ensure practicality in an industrial setting,
24-061
Minimizing Leaching of Al, Co, Cu, Fe, Li, and Ni
During Discharge of Lithium-Ion Batteries
L. A. Sanchez-Calderon
Missouri Univ. of Science and Tech., Rolla, MO
L. Alagha
Missouri Univ. of Science and Tech., Rolla, MO
ABSTRACT
The existing methods for recycling lithium-ion batter-
ies present initial hurdles related to the safe handling and
preparation of the batteries to avert potential explosions.
Submerging batteries in sodium chloride (NaCl) solution
has become an acceptable industrial practice. However, the
use of NaCl to discharge lithium-ion batteries rusts the bat-
teries’ cases and releases metals which impacts the down-
stream processes that involve selective recovery of Li. This
study aimed to determine the optimal concentrations and
pH range of NaCl for the discharge of lithium-ion batteries
for the purpose of minimizing the leach of Al, Co, Cu, Fe,
Li, and Ni.
INTRODUCTION
Lithium-ion batteries contain valuable metals like cobalt,
copper, lithium, and nickel making its recycling economi-
cally very attractive (Ojanen et al., 2018). Recycling these
metals also helps mitigate social and environmental impacts
associated with mining practices of cobalt and lithium
(Banza et al., 2009 Liu &Agusdinata, 2020). There are
two main practices currently adopted by industry to recy-
cle lithium-ion batteries. The first is the pyrometallurgy
approach which consumes high energy and requires a high
initial investment (Zhou et al., 2021). The second is the
hydrometallurgical processing which requires discharging
prior to leaching to avoid potential explosions (Liang et
al., 2021). The discharge reaction is shown in Equation 1
(Bartholome et al., n.d.):
LiC6 +CoO2 → C6 +LiCoO2 (1)
Lithium oxide is still reactive with water, but the reac-
tion occurs at a slower rate than lithium metal with water.
There are primarily two methods for discharging a Li
battery. The first involves connecting the battery to an elec-
tric circuit, which preserves the battery’s shape and other
conditions but is not practical for industrial- scale opera-
tions. The second method entails immersing the battery
in an aqueous solution containing an electrolyte, typically
NaCl. In the latter scenario, the NaCl solution serves as
a conductive medium by facilitating the flow of electrons.
The primary concern with the discharge processes with
NaCl, or other media, is the corrosion of the battery casing
and the release of metals. (Bae &Kim, 2021). The release
of metals is undesirable as they can react with water, gen-
erating heat in the process. Moreover, the loss of valuable
metals during the discharge process is economically unfa-
vorable. Ultimately, it results in increased costs associated
with treating the waste solutions to minimize environmen-
tal impacts. (Li et al., 2010).
To control the release of metals (i.e., Al, Co, Cu, Fe,
Li, and Ni), this study proposed a 2-step procedure. The
first step involved varying the concentration of NaCl in the
submerging solution and studying its impact on battery
case’s corrosion rate at neutral pH. This aimed to select the
optimal concentration at which the corrosion is minimal.
In the second step, adjustments were made to the other key
parameter, namely, pH. The pH is a critical factor as indi-
cated by the Pourbaix diagram shown in Figure 1 (Barnes,
2014). The real challenge associated with this approach was
to attain the maximum time limit of 16 hours, designed to
ensure practicality in an industrial setting,