Front. Phys. DOI 10.1007/s11467-013-0408-7 REVIEW ARTICLE Nanomaterials for electrochemical energy storage Nian Liu 1 , Weiyang Li 2 , Mauro Pasta 2 , Yi Cui 2,3,† 1 Department of Chemistry, Stanford University, Stanford, CA 94305, USA 2 Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA 3 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA Corresponding author. E-mail: † yicui@stanford.edu Received November 7, 2013; accepted December 5, 2013 The development of nanotechnology in the past two decades has generated great capability of con- trolling materials at the nanometer scale and has enabled exciting opportunities to design materials with desirable electronic, ionic, photonic, and mechanical properties. This development has also contributed to the advance in energy storage, which is a critical technology in this century. In this article, we will review how the rational design of nanostructured materials has addressed the challenges of batteries and electrochemical capacitors and led to high-performance electrochemical energy storage devices. Four specific material systems will be discussed: i) nanostructured alloy anodes for Li-batteries, ii) nanostructured sulfur cathodes for Li-batteries, iii) nanoporous open- framework battery electrodes, and iv) nanostructured electrodes for electrochemical capacitors. Keywords nanomaterial, energy storage, silicon anode, sulfur cathode, stationary battery, electrochemical capacitors PACS numbers 81.05.Rm, 85.45.Yz, 82.47.Aa, 82.47.Uv, 88.85.J- Contents 1 Introduction 1 2 Nanostructured high-capacity alloy anodes for Li-batteries 2 2.1 Opportunities and challenges for alloy anodes 2 2.2 Solid nano-Si (Ge, Sn) 3 2.3 Hollow and porous nano-Si (Ge, Sn) 5 2.4 Clamped hollow nano-Si (Ge, Sn) 5 3 Nanostructured high-capacity sulfur cathodes for Li-batteries 8 3.1 Background of lithium-sulfur battery and problems to be addressed 8 3.2 Sulfur-carbon composite cathode and amphiphilic surface modification 8 3.3 Monodisperse hollow and yolk-shell sulfur nanostructures 10 3.4 Lithium sulfide cathode: activation and bifunctional binder 12 4 Nanoporous Prussian Blue analogues for stationary energy storage 13 4.1 Prussian Blue analogues (PBAs) 13 4.2 The open framework nanoporous crystal structure 13 4.3 Electrolyte considerations 15 4.4 PBAs in aqueous electrolyte batteries 15 4.5 Other applications 17 5 Nanostructured electrodes for electrochemical capacitors 17 5.1 Introduction and basics 17 5.2 Conductive paper, textile, and sponge 17 5.3 Nanostructured hybrid carbon-metal oxide 18 5.4 Nanostructured conducting polymer hydrogel 19 6 Conclusion and perspective 20 Acknowledgements 21 References 21 1 Introduction Today’s globally growing efforts towards renewable and clean energy drive the urgent need for major break- throughs in energy storage technology, which is criti- cal in addressing the mismatched supply and demand in time and space associated with renewable energy sources [1]. Among various energy storage systems, electrochem- ical ones, such as rechargeable batteries and electro- chemical capacitors (ECs), are especially attractive for c  Higher Education Press and Springer-Verlag Berlin Heidelberg 2014