Sn Wears Super Skin: A New Design for Long Cycling Batteries

Abstract

Searching for new anode alternatives in lieu of graphite for lithium-ion batteries that can deliver better electrochemical performance to meet the emerging energy/power demands in electric vehicles becomes particularly challenging. We report a rationally designed hybrid composite as anode in LIB that exhibits a greatly improved gravimetric capacity of 727 mAh/g with a Coulombic efficiency of >99.8% after 3000 cycles at 1.0 C. A capacity of 662 mAh/g at a high rate of 5.0 C was obtained after impressively long 10 000 cycles. From the 50th to 10 000th cycle under 5.0 C, the capacity retention is >97% with a negligible decay of <0.00026% per cycle. The excellence in electrochemistry is attributed to the efficient stress relax, accommodable space, lack of agglomeration, and solid-electrolyte interphase consuming Li of a delicate composite configuration that is composed of a Sn kernel wearing adjustable TiO "skin".

Pressure‐Induced Synthesis of Homogeneously Dispersed Sn/SnO2/C Nanocomposites as Advanced Anodes for Lithium‐Ion Batteries

“…04‐0673) (Figure a). These results indicate that SnO is formed first in the pyrolysis of C 2 H 6 OSn at 400 °C, which subsequently is transformed to Sn and SnO 2 by disproportionation reaction at 600 °C . On continuing to increase the temperature, C atoms start reducing SnO 2 to Sn.…”

“…04-0673) [17] (Figure 2a). These results indicate that SnO is formed first in the pyrolysis of C 2 H 6 OSn at 400 C, which subsequently is transformed to Sn and SnO 2 by disproportionation reaction at 600 C. [26] On continuing to increase the temperature, C atoms start reducing SnO 2 to Sn. The SnO 2 is totally reduced to Sn by C at 800 C, thus resulting in the disappearance of crystalline SnO 2 in the sample-III (Figure 2a).…”

“…As Sn/SnO 2 /C shows the best cyclability, its lithium storage performances were further tested. The CV curves show the cathodic peaks at 0.2–0.7 V and anodic peaks at 0.4–0.8 V, which correspond to the formation of Li−Sn alloy phases (Li 4.4 Sn, Li 3.5 Sn, LiSn, and Li 0.4 Sn) and extraction of Li from alloy phases, respectively (Figure a) . According to the first Coulombic efficiency (CE) of 79.9%, the first discharge and charge capacities are obtained as 941.0 and 752.2 mAh g −1 (Figure b), respectively.…”

“…The two peaks appear around 494.82 and 486.41 eV in the sample-I (Figure 2d), which are attributed to Sn 3d 3/2 and Sn 3d 5/2 binding energies of Sn 2þ , [6] again suggesting the formation of SnO. Sample-II shows four Sn peaks of Sn 4þ 3d 3/2 /3d 5/2 at 495.41/486.94 eV and Sn 0 3d 3/2 /3d 5/2 at 493.36/485.02 eV, [7,26] again indicating the existence of Sn and SnO 2 . Sample-III also shows four Sn peaks.…”

“…The two peaks around 493.63 and 485.22 eV are attributed to Sn 0 3d 3/2 and Sn 0 3d 5/2 . [26] The presence of Sn 4þ 3d 3/2 /3d 5/2 at 495.21/486.67 eV may be from surface oxidation of Sn at high temperature. [26] The high intensity of Sn 4þ peak is attributed to the high surface collection density.…”