While sulfur has been an attractive cathode for more than 50 years its viability has been hindered by two fundamental challenges which need to be resolved.1 (1) Enhance the conductivity of elemental sulfur. (Unlike commercial lithium ion cathodes sulfur is a good insulator) (2) Control the diffusion of soluble polysulfide intermediates formed during cycling. Here we demonstrate a sulfur particle embedded with hollow carbon nanospheres which is encapsulated by conductive nanomembranes built based on the layer-by-layer principle (Fig. 1).2 Such architecture has multiple advantages: (A) the hollow carbon embedded inside the sulfur core promotes electronic conductivity and sulfur utilization while minimizing the addition of conductive carbon in the electrode. (B) the hollow space inside the carbon structures can accumulate polysulfides and reduce outwards expansion during discharge. (C) the ion-selective nanomembrane limits the escape of polysulfides while permitting the diffusion of lithium ions (D) nanocarbon is also decorating the membrane to promote conductivity and minimize the carbon loading. This truffle inspired nanoarchitecture overcomes the dilemma associated with maximizing the sulfur loading without compromising the electrical conductivity and retention of polysulfides. Figure 1. Picture of Godiva truffle (A) – our inspiration and a three-dimensional schematic of our concept (B); (C) depicts the typical outer surface of a truffle containing the selective polymer membrane and carbon decoration. A TEM/EELS analysis (D) depicting the embedded carbon (green) the sulfur core (yellow) and the initial (“embryonic”) polymer coating of a sulfur particle (blue). The outer selective membrane and carbon decoration were omitted for clarity. References 1 A. Manthiram, Y. Fu, S.-H. Chung, C. Zu and Y.-S. Su, Chem. Rev., 2014, 114, 11751–11787. 2 C. B. Bucur, J. Muldoon, A. Lita, J. B. Schlenoff, R. A. Ghostine, S. Dietz and G. Allred, Energy Environ. Sci., 2013, 6, 3286–3290.

Nano-membranes for lithium/sulfur batteries

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.