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Yoon et al. Energy Mater 2024;4:400063 https://dx.doi.org/10.20517/energymater.2023.146 Page 19 of 30

Various approaches involving multidimensional structures have been reported for structural control of Sb-
based anodes in PIBs [108-112] . Shi et al. developed a flower-like Sb O Cl cluster, which was prepared by a
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hydrothermal method, for PIB use [Figure 13A] . The flower-like structure provides diffusion paths for K
[108]
ions inserted in parallel along its plane. Furthermore, a flower-like Sb O Cl anode exhibited high reversible
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capacities of 530, 316, and 150 mAh g at rates of 50, 100, and 150 mA g , respectively. Liu et al. suggested
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the use of honeycomb-like porous microsized layered Sb (porous-Sb) [Figure 13B] ; the porous Sb was
[109]
prepared using a template-free hydrothermal method with deionized water. The honeycomb-like porous
structure not only provided efficient K-ion transport but also extra space for accommodating volume
changes. Based on its structural benefits, porous-Sb exhibited good electrochemical cycling stability with an
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initial reversible capacity of 655.5 mAh g and a capacity retention of 84% after 80 cycles at a current rate of
50 mA g . Imtiaz et al. reported Sb deposited on a Cu Si (Sb/Cu Si ) nanowire array as an anode, which
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was synthesized by high-boiling-solvent-mediated vapor-solid-solid growth, with the aim of enhancing the
[110]
electrochemical performance of Sb [Figure 13C] . The Sb/Cu Si nanowire contributed to the outstanding
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electrochemical performance owing to its mechanically robust, highly stable, and distinctive structure.
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Furthermore, the Sb/Cu Si nanowire anode exhibited a high initial reversible capacity of 647.9 mAh g at a
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current rate of 50 mA g and good cycling performance, with a capacity retention of 65% over 1,250 cycles
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at a high 200 mA g rate. Guo et al. proposed an MXene-based aerogel containing single Sb atoms,
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quantum dots, and graphene oxide (Sb-SQ@MA) [Figure 13D] , which was chemically synthesized using
[111]
few-layered MXene (Ti C T ), graphene oxide (GO), and SbCl as precursors. The high electrochemical
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performance of Sb-SQ@MA was achieved through improved charge-transfer kinetics, enhanced K-storage
capability, structural stability, and highly efficient electron transfer. The Sb-SQ@MA anode exhibited a
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stable capacity retention of 94% with a high reversible capacity of 314 mAh g after 1,000 cycles at a fast
current density of 1 A g . Consequently, various structural controls have contributed to the stable high rate
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capability and cycling performance of Sb-based PIB anodes owing to their distinctive structural
characteristics that accommodate volume expansion or facilitate K-ion diffusion. He et al. fabricated a 3D
macroporous Sb@C composite (Sb@C-3DP) using a simple KCl template [Figure 13E] ; Sb@C-3DP
[112]
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showed a reversible capacity of 516 mAh g at 50 mA g , an ICE of 76.2%, and delivered a capacity
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retention of 97% after 260 cycles at 500 mAh g . A full cell with a Prussian blue cathode delivered a
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reversible capacity of 508 mAh g (based on anode mass) at a current rate of 0.2 A g .
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Various strategies, such as alloy or composite formation, have been extensively studied for improving the
electrochemical properties of Sb anodes for PIBs [12,69,70,105,110-119] . Zheng et al. designed Sb nanoparticles
encapsulated in an interconnected carbon-sphere network (Sb/CSN) via an electrospray-assisted strategy
[Figure 14A] . The uniformly dispersed nano-Sb within the porous spherical network mitigated the
[69]
volume change experienced by Sb. In addition, the highly concentrated electrolyte formed a robust KF-rich
SEI on the Sb/CSN surface. Synergy between this interesting structure and the robust SEI greatly enhanced
the electrochemical performance of the Sb/CSN anode, which maintained a reversible capacity of
504 mAh g after 220 cycles at 200 mA g . Shi et al. encapsulated Sb nanoparticles in N-, S-, and F-co-
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doped carbon skeletons (Sb/NSF-C) using a hydrothermal method, heat treatment, and etching
[Figure 14B] . Doping changes the electronic configuration, resulting in defects in the carbon layers. This
[113]
3D porous structure is highly mechanically strong and contributes to enhancing the electrochemical
reaction kinetics. After 200 cycles, the Sb/NSF-C composite retained a reversible capacity of 287 mAh g at
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a current rate of 1.0 A g . Han et al. embedded Sb nanocrystals in an ultrathin carbon nanosheet (Sb/CNS)
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using a one-step solvothermal reaction [Figure 14C] . The mechanical stability of the nanosheet
[114]
accommodated volume changes and suppressed side reactions involving the electrolytes. Moreover, the
large surface area of the nanosheet contributed to fast ionic/electronic diffusion. Consequently, a reversible
capacity of 247 mAh g and up to 90% capacity retention were attained after 600 cycles at 200 mA g .
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Cao et al. created a flexible integrated anode by confining Sb nanoparticles in porous carbon nanofibers