Tin anode 196 Materials c Sn Density(gcm-3) 2.25 7.29 Lithiated phase LiCe Li44Sn Theoretical specific capacity(mAh g-1) 372 994 Theoretical charge density(mAh cm-3) 837 7246 Volume change (% 12 260 Potential vs.Li(~V) 0.05 0.6 Advantages Disadvantage high theoretical huge volume capacity change 中 D environmental pulverization of benignity the electrode 中 low cost poor cycle ability 6
6 Tin anode high theoretical capacity environmental benignity Advantages Disadvantage huge volume change pulverization of the electrode low cost poor cycle ability
Tin anode 96 a 0.8 Li,Sns 入sn LiSn n/.n Li,Sna/Liz2Sns 0 20 40 60 Li content (at.%) apejins Nat.Mater..2013,12,1102 Potentiostatic dealloying (1 V versus Li/Li)results of Sn particle morphologies as a function of Li composition obtained by a single alloying/dealloying cycle in 1 M LiPF6 in ethylene carbonate/diethylcarbonate,1:1 v/v at room temperature.(a)Voltage versus Li content for alloying Li into ~2 um diameter Sn particles at a fixed current of-49.7 mA/gsn.The voltages define the composition of the particles.(b-g)The first row of SEM images corresponds to particle surfaces and the second row to focused ion-beam milled cross sections of the particles.(b,c)Li30Sn.70:the surface is roughened with void nodules,and the particle interior contains ~10 nm-diameter voids(c,inset,size of image,200 nm)that may have formed through a Kirkendall process.These voids are absent in virgin Sn particles.(d.e)Li4Sn52:collapsed bicontinuous morphology yielding a hollow core-shell-like7 structure.(f.g)Lio.Sn23:bicontinuous morphology with a ligament size of 50-100 nm.Scale bars,500 nm
7 Tin anode Potentiostatic dealloying (1 V versus Li+ /Li) results of Sn particle morphologies as a function of Li composition obtained by a single alloying/dealloying cycle in 1 M LiPF6 in ethylene carbonate/diethylcarbonate, 1:1 v/v at room temperature. (a) Voltage versus Li content for alloying Li into ∼2 μm diameter Sn particles at a fixed current of -49.7 mA/gSn. The voltages define the composition of the particles. (b-g) The first row of SEM images corresponds to particle surfaces and the second row to focused ion-beam milled cross sections of the particles. (b,c) Li0.30Sn0.70; the surface is roughened with void nodules, and the particle interior contains ∼10 nm-diameter voids (c, inset, size of image, 200 nm) that may have formed through a Kirkendall process. These voids are absent in virgin Sn particles. (d,e) Li0.48Sn0.52; collapsed bicontinuous morphology yielding a hollow core-shell-like structure. (f,g) Li0.77Sn0.23; bicontinuous morphology with a ligament size of 50-100 nm. Scale bars, 500 nm Nat. Mater. 2013, 12, 1102