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Page 6 of 30 Yoon et al. Energy Mater 2024;4:400063 https://dx.doi.org/10.20517/energymater.2023.146

electrochemical testing. The proposed reaction mechanism for the Sb anode in PIBs during discharging and
charging is summarized by equations (5) and (6), along with the crystallographic schematic shown in
Figure 4.

During discharging:

Sb (Rhombohedral) → K Sb → K Sb (Cubic) (5)
x
3
During charging:

K Sb (Cubic) → K Sb → Sb (Rhombohedral) (6)
3
x
RECENT ADVANCES IN ANTIMONY-BASED ANODES
Owing to its high theoretical gravimetric and volumetric capacities, Sb exhibits significant potential as an
anode material for LIBs, SIBs, and PIBs [Figure 1A and B]. However, the alloying reaction with Li induces
substantial volume changes and internal stresses in the Sb particles [Figure 1C], which leads to
pulverization. Consequently, pulverized Sb particles inevitably form an additional SEI layer through further
reactions with the electrolyte during repeated cycling, resulting in irreversible side reactions [55,71] . Therefore,
researchers have proposed various strategies to address the challenges associated with excessive volume
changes, including SEI layer control, structural control, and composite/alloy formation, to achieve highly
stable cycling and rate capabilities [Figure 5]. This section systematically presents recent research progress
focused on overcoming such drawbacks from the perspectives of SEI layer control, structural control, and
composite/alloy formation.

Sb-based anodes for LIBs
Sb is considered a competitive anode owing to its abundance, metallic properties, high theoretical capacity
(Li Sb: 660 mAh g ), and moderate potential (0.5-0.8 V vs. Li /Li). However, Sb-based anodes undergo
+
-1
3
excessive volume changes (~134%), and the continuous formation and destruction of the SEI layer result in
capacity degradation and electrolyte starvation. To address these issues, recent advances in SEI layer
control, structural control, and composite/alloy formation of Sb-based anode for LIB applications have been
reported.

Researchers have explored the use of various solvents and salts to improve the SEI layer properties of Sb-
based anodes [72-74] . Bian et al. reported incorporating fluoroethylene carbonate (FEC) into a propylene
[72]
carbonate (PC) electrolyte in the LIB system . This approach facilitates the construction of a stable SEI
layer on a microsized Sb anode during Li cycling [Figure 6A]. Analysis using first-principles calculations,
X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) revealed that FEC has a
lower LUMO (the lowest unoccupied molecular orbital) energy level (-0.11 eV) compared to PC (0 eV). The
FEC additive decomposes ahead of PC to create a LiF-rich SEI layer on the Sb surface that suppresses
continuous electrolyte decomposition and contributes to facile ion/electron transfer and structural stability
-1
during repeated cycling. Furthermore, the microsized Sb exhibited a high reversible capacity of 575 mAh g
-1
and a high ICE of 81% after 70 cycles at a high current rate of 5 A g . Sun et al. developed a non-flammable
triethyl phosphate (TEP)/1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE) electrolyte to
[73]
improve the stability of a bulk Sb anode [Figure 6B] . The solvation structures formed by lithium
bis(fluoroslufonyl)imide (LiFSI)-TEP/HFE exhibited distinct dipole-dipole interactions that provided
excellent kinetics and compatibility with the anode material. Therefore, the bulk Sb anode showed a highly
reversible capacity of 604 mAh g with a substantial capacity retention of 92% after 100 cycles at a current
-1