A case study 思 D0:10.1002/adma.200701364 Tin-Nanoparticles Encapsulated in Elastic Hollow Carbon Spheres for High-Performance Anode Material in Lithium-Ion Batteries** By Wei-Ming Zhang,Jin-Song Hu,Yu-Guo Guo,Shu-Fa Zheng,Liang-Shu Zhong, Wei-Guo Song,and Li-Jun Wan* 24wt%20 Nanostructured tin dispersed in a carbon matrix In the present work,we therefore designed a new approach to synthesize tin nanoparticles encapsulated elastic hollow carbon and carbon-encapsulated hollow tin nanopartides were also spheres (TNHCs)with uniform size,in which multiple tin reported as superior anode materials.These studies showed nanoparticles with a diameter of less than 100 nm were encap- that both coating tin nanomaterials with carbon layer and sulated in one thin hollow carbonsphere with a thickness ofonly dispersing tin nanoparticles in carbon matrix are effective to about 20 nm,thus leading to both the content of Sn up to over improve their electrochemical properties in lithium ion batter-70%by weight and the void volume in carbon shell as high as ies.It is obvious that the higher content of and smaller size of tin,about 70-80%by volume.This void volume and the elasticity of as well as the thinner carbon coating will greatly contribute to thin carbon spherical shell efficiently accommodate the volume the further enhancement of material performance since the change of tin nanoparticles due to the Li-Sn alloying-dealloying lithium storage density in tin is much higher than that in carbon.reactions,and thus prevent the pulverization of electrode.As a Meanwhile,this tin-based anode material has to be designed to result,this type of tin-based nanocomposites have very high own enough void volume to compensate the volume expansion specific capacity of>800 mA h g in the initial 10 cycles,and during Lit insertion,which is important to improve its cycle >550mA hgafter the 100th cycle,as well as excellent cycling performance. y9 A case study