Dual-Carbon-Confined SnS Nanostructure with High Capacity and Long Cycle Life for Lithium-ion Batteries

SnS with high theoretical capacity is a promising anode material for lithiumion batteries.However,dramatic volume changes of SnS during repeated discharge/charge cycles result in fractures or even pulverization of electrode,leading to rapid capacity degradation.To solve this problem,we construct a dual-carbon-confined SnS nanostructure(denoted as SnS@C/rGO)by depositing semi-graphitized carbon layers on reduced graphene oxide(rGO)supported SnS nanoplates during high-temperature reduction.The dual carbon of rGO and in situ formed carbon coating confines growth of SnS during the high-temperature calcination.Moreover,during the reversible Li+storage the dual-carbon modification enables good electronic conductivity,relieves the volume effect,and provides double insurance for the electrical contact of SnS even after repeated cycles.Benefiting from the dual-carbon confinement,SnS@C/rGO exhibits significantly enhanced rate capability and cycling stability compared with the bare and single carbon modified SnS.SnS@C/rGO presents reversible capacity of 1029.8 mAh g^(-1)at 0.2 A g^(-1).Even at a high current density of 1 A g^(-1),it initially delivers reversible capacity of 934.0 mAh g^(-1)and retains 98.2%of the capacity(918.0 mAh g^(-1))after 330 cycles.This work demonstrates potential application of dual-carbon modification in the development of electrode materials for high-performance lithium-ion batteries.

Microsized SnS/Few-Layer Graphene Composite with Interconnected Nanosized Building Blocks for Superior Volumetric Lithium and Sodium Storage

To develop anode materials with superior volumetric storage is crucial for practical application of lithium/sodium-ion batteries.Here,we have developed a micro/nanostructured Sn S/few-layer graphene(Sn S/FLG)composite by facile scalable plasma milling.Inside the hybrid,SnS nanoparticles are tightly supported by FLG,forming nanosized primary particles as building blocks and assembling to microsized secondary granules.With this unique micro/nanostructure,the Sn S/FLG composite possesses a high tap density of 1.98 g cm^(-3)and thus ensures a high volumetric storage.The combination of Sn S nanoparticles and FLG nanosheets can not only enhance the overall electrical conductivity and facilitate the ion diffusion greatly,but alleviate the large volume expansion of Sn S effectively and maintain the electrode integrity during cycling.Thus,the densely compacted Sn S/FLG composite exhibits superior volumetric lithium and sodium storage,including high volumetric capacities of 1926.5/1051.4 m Ah cm^(-3)at 0.2 A g^(-1),and high retained capacities of 1754.3/760.3 m Ah cm^(-3)after 500cycles at 1.0 A g^(-1).With superior volumetric storage performance and facile scalable synthesis,the Sn S/FLG composite can be a promising anode for practical batteries application.

Construction of SnS-Mo-graphene nanosheets composite for highly reversible and stable lithium/sodium storage

Sn-based chalcogenides are considered as one of the most promising anode materials for lithium-ion batteries(LIBs)because of their high capacities through both conversion and alloying reactions.However,the realization of full capacities of Sn-based chalcogenides is mainly hindered by the large volume variation and inferior reversibility of conversion reaction during cycling.In present work,a new ternary Sn SMo-graphene nanosheets(Sn S-Mo-GNs)composite is fabricated by a simple and scalable plasma milling method,in which Sn S nanoparticles are tightly bonded with Mo and GNs.The Mo and GNs additives can effectively alleviate the large volume change of Sn S upon cycling,which leads to a stable electrochemical framework.Moreover,they can significantly suppress the Sn agglomeration in lithiated Sn S,which enables highly reversible conversion reaction during cycling.As anode for LIBs,the Sn S-Mo-GNs composite exhibits a high initial coulombic efficiency of 86.9%(almost complete reversibility of Sn S,~97.3%),high cyclic coulombic efficiency after initial three cycles(>99.5%),and long lifespan(up to 600 cycles).Moreover,it also demonstrates superior electrochemical performance for sodium storage.Thus,this work demonstrates a potential anode for batteries application and provides a viable strategy to obtain highly reversible and stable anodes for lithium/sodium storage.