The request for high energy lithium ion density batteries pushes forward the research on materials which could store more lithium atoms such as Si, Sn and so on. For example, Si and Sn could store 9786 and 7246 mAh/cm3. However, high capacity materials have the large volume changes during charge/discharge and leads to rapid degradation (Figure a). 3D scaffolded electrodes could accommodate the volume change and mitigate capacity loss. We have developed a route of fabricating 3D bicontinuous electrodes which consist of an inactive 3D scaffold and a conformal coating of active materials[1-6]. The nickel scaffold is derived from polystyrene opal templates (Figure b). Sn alloy is electrodeposited onto the 3D scaffold  (Figure c). Such a scaffolded structure could hold the active material, efficiently conduct electrons, and partly manage the stress-induced capacity decay. The electrochemical analysis confirms that the inert 3D metal scaffold could stabilize the alloy electrode and significantly improve the cyclability of high capacity anodes. With the progress in the Sn anode[4], we also applied the similar concepts to silicon and metal oxide anodes, which are coated to the scaffold by CVD and hydrothermal methods[5-6]. Summarizing the research on Sn, Si, metal oxide leads to a conclusion that well-design scaffold structure and conformal coating are two key factors which contribute to the performance improvement of high capacity anodes. 

References

[1]. Zhang, H.; Braun, P.V. Nature Nanotechnol. 2011, 6, 277.

[2]. Pikul, J.H.; Zhang, H.; Cho, J.; Braun, P.V.; King W. Nature Commun. 2013, 4, 1732.

[3]. Yu, X; Zhang, H.; Oliverio, J.K.; Braun, P.V. Nano Lett. 2009, 9, 4424.

[4] Zhang, H.; Shi, T.; Wetzel, D.J.; Nuzzo R.; Braun, P.V. Adv. Mater. 2015, DOI: 10.1002/adma.201504780

[5]. Zhang, H.; Braun, P.V. Nano Lett. 2012, 12, 2778.

[6] Liu, J.; Zhang, H.; Wang, H.; Cho, J.; Pikul, J.H.; Epstein, E.S.;  Huang, X.;  Liu, J.;  King, W.P.; Braun, P.V. Adv. Mater. 2014, 26, 7096-7101.