3D macroporous electrode and high-performance in lithium-ion batteries using SnO2 coated on Cu foam

Abstract

A three-dimensional porous architecture makes an attractive electrode structure, as it has an intrinsic structural integrity and an ability to buffer stress in lithium-ion batteries caused by the large volume changes in high-capacity anode materials during cycling. Here we report the first demonstration of a SnO2-coated macroporous Cu foam anode by employing a facile and scalable combination of directional freeze-casting and sol-gel coating processes. The three-dimensional interconnected anode is composed of aligned microscale channels separated by SnO2-coated Cu walls and much finer micrometer pores, adding to surface area and providing space for volume expansion of SnO2 coating layer. With this anode, we achieve a high reversible capacity of 750 mAh g−1 at current rate of 0.5 C after 50 cycles and an excellent rate capability of 590 mAh g−1 at 2 C, which is close to the best performance of Sn-based nanoscale material so far.

SnO2-Coated 3D Etched Cu Foam for Lithium-ion Battery Anode

“…3c) confirms the existence of Cu 2+ on the surface of SnO 2 -coated Cu foam, in accordance with the partial re-oxidation during the SnO 2 coating process (Fig. 3a) [11,[18][19][20]. In Sn 3d spectrum of the SnO 2 /Etched Cu foam (Fig.…”

“…After that, the absence of CuO in Etched Cu foam after H 2 shows a result of the effective reduction of CuO into metallic Cu. SnO 2 (JCPDS 41-1445; as indicated by orange bar) phase is identified in the SnO 2 /Etched Cu foam [11], and meanwhile the re-appearance of CuO indicates that the partial oxidation of Cu foam occurs again during the SnO 2 sol-gel coating process. XPS analysis was used for the determination of chemical environment and oxidation state of copper.…”

“…The etched Cu foam was dried at 100 C in vacuum for 24 h, and a heat treatment was carried out at 500 o C under H 2 atmosphere during 5 h for a reduction of copper oxide to metallic copper in the etched Cu foam. After that, for a SnO 2 coating process, the solgel method based on our reports for the fabrication of SnO 2 -coated Cu foam was applied also in this study [10,11]. The commercially available Cu foam, the Cu foam after etching by the electroless plating, the Cu foam after the H 2 heat-treatment, and the Cu foam after the SnO 2 coating were referred to as Pristine Cu foam, Etched Cu foam, Etched Cu foam after H 2 , and SnO 2 /Etched Cu foam, respectively.…”

“…Substantial efforts have been dedicated for addressing the issue of large volume changes in SnO 2 anode material, especially through the unique nanostructuring of high-capacity material combined with the integrated electrode design wherein both the void space for alleviating the volume changes and the current collector integrated, and binder-and carbonagent free electrode for having the structural integrity can be achieved [7][8][9][10][11][12][13][14]. Among the various morphology controls of high-capacity materials from zerodimensional (0D) to three-dimensional (3D), the 3D architectures such as inverse opal scaffold [7,8], nanofoam [9][10][11][12], and long chains of particles [13,14] have attracted great attention as a smart electrode prototype. To obtain the stable and high energy density in the SnO 2 electrode by using the 3D integrated electrode concept, in our previous reports we pre-pared the two types SnO 2 -coated Cu foams, using commercially available Cu foam and freeze-castingderived Cu foam, through sol-gel coating method [10,11].…”

“…Among the various morphology controls of high-capacity materials from zerodimensional (0D) to three-dimensional (3D), the 3D architectures such as inverse opal scaffold [7,8], nanofoam [9][10][11][12], and long chains of particles [13,14] have attracted great attention as a smart electrode prototype. To obtain the stable and high energy density in the SnO 2 electrode by using the 3D integrated electrode concept, in our previous reports we pre-pared the two types SnO 2 -coated Cu foams, using commercially available Cu foam and freeze-castingderived Cu foam, through sol-gel coating method [10,11]. Compared to the conventional SnO 2 nanoparticle electrode, the superiority of 3D interconnected Cu scaffolds was demonstrated in the high lithium storage and also the rate capability, by preserving their original architecture upon cycling.…”