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Rehman et al. Energy Mater 2024;4:400068 https://dx.doi.org/10.20517/energymater.2024.06 Page 15 of 64

Figure 7. (A) (a) Schematic representation for synthesis of Sn P HS@MXene nanocomposite. SEM images of (b) Sn P HS and
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(c) Sn P HS@MXene nanohybrids. (d) EDX mapping and elemental analysis of Sn P HS@MXene. (e) TEM images of Sn P HS, (f)
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Sn P HS@MXene hybrid, and (g) HRTEM images of Sn P HS@MXene. (B) Electrochemical performance of the Sn P HS@MXene
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hybrid in full SIB cell. (a) Charge/discharge capacity at various ampere densities, and (b) cyclic stability at 100 Ma g and 1 A g .
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Reproduced with permission from . Copyright © 2023 Elsevier.
conductive frameworks both horizontally and vertically to MXene planes. Additionally, metallic Sn
nanoparticles imparted further to the conductivity of the composite. This hybrid combination of conductive
matrices synchronously activated tin phosphide electrochemically, leading to enhanced specific capacity.
Volume changes of Sn and tin phosphides were coped by Sn/MXene during discharging/recharging cycles
to enable the anode to deliver an ultra-stable cycle life with a capacity of 143.1 mAh g over 1,000 cycles at
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2 A g . A capacity of 127.8 mAh g over 1,000 cycles at a current of 5 A g was retained under the
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capacitive-dominated mechanism. Another multiphasic graphene encapsulated Sn P and SnP hybrid
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showing high aptitude for SIB anodes has been reported to offer long cyclic stability and capacity . Volume
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buffering offered by the encapsulated graphene shell, together with improved capacity, enabled the
fabricated anode to sustain suitable capacity. An ICE of 53.6% was achieved under a pseudocapacitive
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storage process, whereas a capacity of 203.1 mAh g at 1 A g over 300 cycles was retained. Finally,
electrochemical performances of representative tin-based anode materials explored for SIBs were compared.
Antimony-based anodes for SIBs
Antimony (Sb) has been ranked as one of the most promising SIB anodes with desirous properties,
including high conductive character (electrical conductivity about 2.56 × 10 Sm ), suitable theoretical
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capacity (660 mAh g for Na Sb alloy), and low operational potential (about 0.5 V). However, as with other
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alloying anodes for SIBs, Sb also has many shortcomings that have plagued its utility on a commercial scale.
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Primarily, complex amorphous structural evolutions having different alloying capabilities with Na and
finally reaching full sodiation in the crystalline structure of Na Sb are still not well understood yet as
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intermediate states are difficult to be probed using XRD and other common techniques. CV charge/
discharge curves of Sb have revealed a two-step sodiation process.