Meanwhile, the porous strcucture and CNTs can effectively alleviate volume changes in battery cycling process.
The flexible S-rGO paper not only provides a conductive framework for electron transport but also alleviates volume effect during cycling.
The rational design of the nanostructure could improve the transportation of electrons/ions and effectively alleviate volume changes of Fe2O3 during the electrochemical cycling.
Compared to ZnS@C, the polyhedron composite presented significantly improved sodium-storage performance with good cycle stability and high specific capacity, ascribed to the cooperative contributions of ZnS, Sb2S3, and C components and a stable structure with sufficient space to alleviate volume variation on cycling.
The rationally designed structures of the CuS/graphene composites offered stable-hosts for Li+ insertion and alleviated the volume changes upon cycling.
The observed excellent electrochemical performance is attributed to the presence of MWCNTs interconnecting the NiO microspheres of the composite material, of which electronic conductivity was improved, and the mesoporous hollow structure effectively alleviated the volume changes to maintain the structural stability during cycling.
These features not only enhanced the electronic properties and alleviated the volume variation of metal selenides during the repeated cycles, but also produced more active sites for lithium storage and a shorter lithium diffusion pathway to expedite the fast charge transfer and preserve a stable SEI layer, resulting in outstanding lithium storage performance.
The electrochemically inactive and thermodynamically stable compounds in reaction 1 and 2 are also responsible for the low efficiency in the first charge-discharge cycle, but they may form a stable scaffolding that alleviates volume expansion related issues associated with lithiation of Si52.
Therefore, when Sb reacts with Li at about 0.8 V, Si and ZnO would buffer the volume expansion for Sb; when discharged to about 0.5 V, Si and Sb would alleviate the volume effect of ZnO; Sb and ZnO would inhibit the volume change for Si when the voltage decrease to about 0.2 V.
Meanwhile, the free voids between neighboring Si nanocrystals alleviate the volume change of Si during cycling.
