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Rehman et al. Energy Mater 2024;4:400068 https://dx.doi.org/10.20517/energymater.2024.06 Page 9 of 64

current rate of 2 A g -1[86] . Ding et al. have designed a 0D/2D heterostructure of SnS quantum dots (QDs)
2
[87]
with N-doped Ti C T MXene . Controlled nucleation and growth during the hydrothermal process were
3
2 x
achieved by using N-methyl pyrrolidone, leading to a uniform growth of SnS QDs of around 3 nm onto the
2
Ti C T MXene matrix. The NH generated during decomposition of the sulfur precursor allowed for in situ
3
3 2 x
N-doping of Ti C T MXene, which significantly improved the interfacial Na transport. The composite
+
2 x
3
delivered impressive sodium storage features, including a high specific capacity of 763.2 mAh g at
-1
100 mA g and an extended cyclic stability (345.3 mAh g at 100 mA g over 600 cycles).
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-1
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Controlled interlayer distances in a material can be constructed with another strategy that can ensure the
provision of suitable ion transfer pathways. In this regard, a uniquely designed material, SnS /reduced GO
2
(rGO), with extended interlayer spacing has recently been presented by Jiang et al. . They introduced
[88]
polyethylene glycol (PEG) as an intercalant. The PEG-SnS /rGO composite had a conductive graphene
2
channel that ensured high conductivity and an efficient charge transfer process. C-S covalent bonds also
strongly cohered C-S covalent bonds between the graphitic skeleton and SnS , which enabled their
2
structural integrity during (de)sodiation. After 100 cycles at 0.1 A g , a capacity of 770 mAh g was attained
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-1
-1
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with an equally competing rate performance capacity of 720 mAh g at 2 A g . A 3D 1T-SnS structure
2
wrapped with graphene (1T-SnS /rGO) has been synthesized onto Ni foam by chemical vapor deposition
2
(CVD) and spray coating . The unique compositing with 1T phase and rGO coating was chosen as an SIB
[89]
anode. It showed initial charge and discharge capacities of 748.7 and 768.8 mAh g , respectively [coulombic
-1
efficiency (CE) = 97.4%], along with a capacity retention of 84.6% after 100 cycles.
Similar to graphene, SnS and SnS from n- and p-type semiconductors have a unique layered structure. The
2
interface between the two materials develops a p-n junction when they are joined to produce a
heterostructure, Sn-SnS . This p-n junction generates an electric field that can facilitate the electron transfer
2
across the material. A monolithic composite SnS-SnS @GO was constructed by a single-step solvothermal
2
[90]
method . Multilayered SnS-SnS @GO heterostructured nanosheets exhibited high capacity and stability as
2
an anode for SIBs. After 100 cycles, the capacity sustained by the anode was 450.6 mAh g (CE = 69.8%).
-1
The capacity sustainability in the composite was commended by the presence of GO, which could alleviate
volume expansion effects of the intrinsic SnS-SnS material to a certain degree and give excellent cyclic
2
stability.
Yang et al. have recently proposed a ZnS/SnS hybrid with N-doped C-fiber encapsulating the ZnS/SnS -like
2
2
beads on the thread, as shown in Figure 3A . The material showed excellent structural and capacity
[91]
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retention, as shown in Figure 3B. In the SIB anode, the material retained a capacity of 174.5 mAh g after
1,000 cycles (CE 62%). Its rate performance showed a capacity suspension of ~312 mAh g at 2 A g , while a
-1
-1
-1
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capacity of 601.1 mAh g was restored after reducing the current to 0.1 A g . Huang et al. have presented an
optimized SIB anode composed of SnO @SnS heterostructured QDs (HQDs) evenly embedded on
2
2
[92]
N-doped graphene (SnO @SnS @NG) . The uniform patterning of SnO @SnS on NG was assured by
2
2
2
2
4+
electrostatic interaction between NG and Sn . DFT calculations showed effectiveness of hetero-interfaces in
electron transport kinetics compared to SnO and SnS alone. The synergistic influence of low ion diffusion
2
2
pathways and high ion diffusion coefficient benefited from the quantum-sized morphology with the dual
benefit of added electrical conductivity by the graphitic network, which resulted in a superb SIB anode
capacity of 450 mAh g at a current density of 0.05 A g and a capacity of 75 mAh g at a current density of
-1
-1
-1
5 A g .
-1
A heterostructured SnS /Mn SnS /C hybrid has been developed using a simple methodology [Figure 4A],
4
2
2
[93]
showing a high SIB anode capacity . A prominent capacity (841.2 mAh g ) with a high ICE of 90.8% was
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