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Page 18 of 64 Rehman et al. Energy Mater 2024;4:400068 https://dx.doi.org/10.20517/energymater.2024.06

Figure 9. (A) (a and b) Charge/discharge profiles of Sb/NiSb and Sb anodes. (c) Cyclic performances of Sb/NiSb and Sb anodes at
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100 mA g for 100 cycles. (d) Rate performances at different ampere densities (0.1-2 A g ). (B) (a and b) SEM images of Sb/NiSb and
Sb-derived anodes after 100 cycles. (c and d) Digital photos of Sb/NiSb and Sb anodes after 100 cycles. (C) (a) Contour mapping (left)
of Operando XRD results and corresponding charge/discharge profile (right); (b) Three-dimensional (3D) view graphics between 24°
and 54° and (c) 54°-72° of the Sb/NiSb electrode. (D) (a) TEM, (b) SAED, (c) HR-TEM patterns of the fully sodiated Sb/NiSb anode
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(0.02 V vs. Na/Na ). Reproduced with permission from [117] . Copyright © 2020 Elsevier.
intact structure with SEI surface coverage without cracks in contrast to the Sb anode with prominent cracks
and no SEI layer visible on the surface of the cycled electrode material. Digital photographs of the same
cycled electrode materials also showed that, unlike the Sb/NiSb electrode material that was intact to the Cu
collector without delamination, the Sb anode material got delaminated from the current collector almost
completely [Figure 9B]. Detailed in-situ XRD [Figure 9C] and ex-situ HRTEM [Figure 9D] analysis paved
the way for deep understanding of the mechanism of the (de)sodiation. It was concluded that the initial
disappearance of Sb and NiSb peaks during initial sodiation resulted in Na Sb hexagonal phase formation in
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multistep sodiation. Additionally, amorphous Ni and Na CO were formed (by decomposition to form SEI).
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During desodiation, the amorphous Sb formation was traced along with amorphous Ni, which contributed
to the electrical conductivity.
A Mo Sb intermetallic SIB anode with extra high capacity has been presented previously by
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[118]
Baggetto et al. . It retained a rated capacity of 280 mAh g at a very high current rate of 30 C. Recently,
[119]
SnSb hybrid with CNF/CNT with a good integration strategy has been reported . It showed a high sodium
storage capacity of 210 mAh g at 0.5 A g over 700 cycles and sustained a capacity of 161 mAh g at 1 A g
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over 1,000 cycles. The suitable interconnected 3D CNT/CNF framework could help sustain dispersion of
SnSb without aggregation. The framework structure ensured efficient electronic transport and multiple
ionic pathways for fast sodium ion transport.