In addition to hollow or porous materials, SnO or SnO2 NSs areanother type of unique nanostructure that might be utilized to achievethe same goal. The idea of creating such a sheet-like structure isto provide a short diffusion path for more efficient lithium transport.20,21At the same time, the presence of the voids between theNS structures will not only relieve the structural alterations caused bythe charge–discharge process, thus improving the cycling performance,but also help to store more lithium. However, compared toanatase TiO2, much less development has been made in the synthesisof SnO or SnO2 nanosheets.5,22–26Herein, we employ new chemistry to synthesize organized flowerlikeSnO2 nanosheets, which can be further assembled into hollowspheres in the presence of templates (see ESI†, Experimental section).Our strategy is based on in situ growth of SnOx (x ¼ 1 or 2) nanosheetsin the sulfonated gel matrix of polystyrene hollow spheres(sPSHS).27,28 Due to the presence of hydrophilic and negative functionalgroups (–SO3), the positively charged precursor Sn2+ ions caneasily adsorb on the surface of the sulfonated polystyrene spheres dueto the electrostatic interaction; thus SnOx NSs will grow within thepolymer gel shell and subsequently develop into a hierarchicalstructure. Use of sPSHS templates can effectively reduce the amountof gas outflux during the template removal by combustion. Asa result, hollow spheres assembled from SnO2 NSs can be wellpreserved.We subsequently studied the electrochemical properties ofthese SnO2 NSHSs for their possible use in LIBs, and the sampledemonstrates significantly improved cycling performance.
đang được dịch, vui lòng đợi..
