Rational Design of Bimetal–Organic Framework-Derived ZnSnS₃ Nanodots Incorporated into the Nitrogen-Doped Graphene Framework for Advanced Lithium Storage

Abstract

Owing to their abundant resources and high theoretical capacities, nanostructured metal sulfides exhibit attractive potential to be used as anode materials for lithium-ion batteries. However, engineering complex metal sulfide nanostructures is still an urgent challenge to achieve advanced performance, enhancing the electrical conductivity and maintaining the structural integrity. Herein, a facile and novel strategy is rationally designed to fabricate ZnSnS3 nanodots directly derived from bimetal (Sn/Zn)–organic frameworks, which are encapsulated into the interconnected three-dimensional N-doped graphene framework (denoted as ZnSnS3@NG). In this hierarchical architecture ZnSnS3@NG, the synergistic effect of high-capacity ZnSnS3 and the superior-conductive graphene network provides a stable structural framework to restrain the structure pulverization without agglomeration and shortens the charge transport pathways simultaneously, significantly enhancing the Li+-storage capability. As expected, the ZnSnS3@NG composite can deliver an excellent reversible capacity of 1354 mA h g–1 at 1 A g–1. Meanwhile, it obtains a high reversible capacity of 516.5 mA h g–1 after 1500 long cycles at an ultrahigh rate of 5 A g–1, with capacity retention as high as 98.55%. This well-designed strategy can pave a way for rational construction of bimetallic sulfides with excellent performance in energy-storage area.

Recent progress in metal–organic framework/graphene-derived materials for energy storage and conversion: design, preparation, and application

“…The sulfur atoms with high electronegativity can extract electrons from metal atoms for facilitated electron transport. 144 Using a MOF/ graphene composite as a precursor to synthesize metal suldes has been extensively studied and various methodologies have been developed till now, including solid-state methods by annealing a mixture of precursor and S powder at high temperatures, 72,76,[145][146][147][148][149][150] solution-phase methods (e.g., hydrothermal or solvothermal vulcanization reaction) using thioacetamide, 107,[151][152][153] thiourea, 154 or Na 2 S 92,155 as a sulfur source, and gas-solid reaction methods using H 2 S/argon as a reducing gas 156 or direct carbonization of a S-containing precursor in inert gas. 157 Thus, many kinds of metal sulde have been obtained, such as FeS, 60 FeS 2 , 63,145,146 152 CoZnNiS, 155 and so on.…”

“…8e). 151 Owing to the different redox potentials of the two metals, the self-matrix and selfconductivity effect would present simultaneously during the alloying/dealloying process, thus guaranteeing faster charge transfer and effective buffer for the reactive intermediate in lithium storage applications. 158 In addition, Qu et al prepared a hierarchically porous hybrid electrode material through in situ sulfuration of a Ni-MOF-74/rGO architecture in H 2 S/argon mixed gas (Fig.…”

“…Combining metal compounds with graphene to form a hybrid material can effectively solve these problems because of the excellent conductivity and confinement effect of graphene. Based on these understandings, various metal compounds/graphene have been synthesized, including Fe 2 O 3 /RGO, 39,41,62,75,105 Fe–Co oxide@GA, 80 ZnO/C/rGO, 86 rGO/Co 3 O 4 , 95,130,133 3DGN/CuO, 109 MnO/C@rGO, 134 3DG@Co 0.85 Se@C, 204 N–ZnSe@rGO, 87 FeP@C/rGO, 98 ZnSnS 3 @NG, 151 etc . 140,143 Among them, our group deliberately synthesized a 3D graphene/Fe 2 O 3 aerogel (3DG/Fe 2 O 3 ) with porous Fe 2 O 3 nanoframeworks well encapsulated within a graphene skeleton by employing a 3DG/MOF aerogel as a template ( Fig.…”

“…, hydrothermal or solvothermal vulcanization reaction) using thioacetamide, 107,151–153 thiourea, 154 or Na 2 S 92,155 as a sulfur source, and gas–solid reaction methods using H 2 S/argon as a reducing gas 156 or direct carbonization of a S-containing precursor in inert gas. 157 Thus, many kinds of metal sulfide have been obtained, such as FeS, 60 FeS 2 , 63,145,146 Fe 7 S 8 , 76 NiS, 156 NiS 2 , 147 Ni 7 S 6 , 154 Co 9 S 8 , 150 Co 9− x Fe x S 8 , 92 CoFeS 2 , 148 ZnSnS 3 , 151 CuCoS, 152 CoZnNiS, 155 and so on.…”

Role of binary metal chalcogenides in extending the limits of energy storage systems: Challenges and possible solutions

“…They presented a onestep hydrothermal process to grow ultrathin NiCo 2 S 4 nanosheets on reduced graphene oxide (rGO) to form a sheet-on-sheet hybrid nanostructure in a mixed solution of water and ethylenediamine (En) at 200°C using Ni(NO 3 ) 2 •6H 2 O and Co(NO 3 ) 2 •6H 2 O as precursors. Later on, many other BMCs with various morphologies including nanopartilces [128][129][130][131] nanosheets [118,127], nanorods [119], nanowires [120], platelike nanocrystals [124], nanodots [132], and cubes [133] have been composited with pure graphene or nitrogen/sulfur co- doped graphene. Although a lot of BMC-graphene compositebased investigations have been reported by several groups for high electrochemical performance, the bonding between graphene and BMCs is weak to immobilize BMCs onto the graphene sheets, leading to easy detachment of BMCs from conductive graphene matrix, which results in fast capacity fade and poor cycling stability.…”