Nano Today 25 (2019) 99–121 Contents lists available at ScienceDirect Nano Today jou rnal homepage: www.elsevier.com/locate/nanotoday Review Nanostructured metallic transition metal carbides, nitrides, phosphides, and borides for energy storage and conversion a,b,1 b,1 b,c b Khang Ngoc Dinh , Qinghua Liang , Cheng-Feng Du , Jin Zhao , b d,∗ a,b,∗ Alfred Iing Yoong Tok , Hui Mao , Qingyu Yan a Energy Research Institute @ NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, Singapore, 637553, Singapore b School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore c State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, Northwestern Polytechnical University, Xi’an, Shaanxi, PR China d College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610068, PR China a r t i c l e i n f o a b s t r a c t Article history: Metallic-like transition metal-based nanostructures (MLTMNs) has recently arisen as robust and highly Received 28 November 2018 efficient materials for energy storage and conversion. Owning to extraordinary advantages over the semi- Received in revised form 17 January 2019 conducting/insulating ones (in terms of fast reaction kinetics, rapid electrical transport, and intrinsically Accepted 26 February 2019 high activity) combined with the high natural abundance, this class of materials is progressively devel- Available online 15 March 2019 oped towards commercial applications in real energy technologies. This review summarizes and discusses the progress in energy storages and conversions that employ MLTMNs. After the introduction and funda- Keywords: mental characteristics, developments in synthetic methodologies of MLTMNs and its application in energy Metallic transition metal-based nanomaterials storage and conversion are provided with more attention on strategies to improve electrochemical per- formances. Personal outlook on the challenges and opportunities of MLTMNs for industrial applications Enhanced electrical conductivity Energy conversion in real energy technologies are proposed and discussed in the conclusion. Energy storage © 2019 Elsevier Ltd. All rights reserved. Electrochemical water splitting Lithium ion battery Contents Introduction . 100 Phosphides. .100 Synthetic methodologies of (MTMPs) . 101 Organic Phosphines (Oil-phase synthesis/ solution-phase) for MTMPs synthesis. .101 Inorganic P and elemental P sources for MTMPs synthesis . 101 Applications of MTMPs for Energy storage and conversion with strategies for enhancing performances . 102 Electrode materials (Batteries and Supercapacitors) . 102 Electrocatalysts (HER, OER, and ORR) . 103 Carbides. .105 Synthetic methodologies for MTMCs . 105 Applications of MTMCs for Energy storage and conversion with strategies for enhancing performances. .107 Electrode materials (Supercapacitors and batteries) . 107 Electrocatalysts (HER, OER, and ORR) . 107 Nitrides . 108 Synthesis of MTMNs . 109 Applications of MTMNs . 109 ∗ Corresponding author. E-mail addresses: [email protected] (H. Mao), [email protected] (Q. Yan). 1 These authors contributed equally to this work https://doi.org/10.1016/j.nantod.2019.02.008 1748-0132/© 2019 Elsevier Ltd. All rights reserved. 100 K.N. Dinh et al. / Nano Today 25 (2019) 99–121 Electrode materials (Supercapacitors and Batteries) . 109 Electrocatalysts (HER, OER, and ORR) . 111 Borides . 111 Synthetic methodologies . 112 Applications of MTMBs . 112 Summary and outlook . 113 Acknowledgements . 118 References . 118 Introduction Table 1 a Metallic-like properties of carbides, nitrides and metal-rich phosphides . Repro- duced with permission from [9] Copyright 2008, Wiley-VCH. With the observation about the depletion of easily accessible Phosphides and Nitrides fossil fuels and climate changes, the exploration of renewable form Carbides of energy conversions and energy carriers have turned out to be Electrical resistivity (␮ cm) 10 – 80 900 – 25000 an important research topic. Regarding energy storage devices, 11 3 ◦ −1 Hall coefficient (10 m C ) −200 to 30 Unavailable secondary lithium/sodium-ion batteries (LIBs/ SIBs) and superca- 6 −1 Magnetic susceptibility (10 emu mol )6– 30 110 – 260 pacitors are considered as the key enabling devices [1]. Up to −1 −1 Heat capacity (J mol K ) 30 – 80 20 – 50 now, they have partly met our demands for compact but powerful a Principally, Group 4–8, first row. energy storage. However, extending their application towards elec- tric vehicles, military & aerospace applications, etc. requires much higher performance by means of rate capability, safety, energy den- sity, and cyclability. To achieve those goals, the development of new tization, isomerization, reforming, hydroprocessing, and water-gas electrode materials plays a crucial role. As for energy conversion shift) [9], there is still lots of interest and room for developments technologies, transforming renewable energy (eg. wind, solar, etc.) in their potential applications of improving existing battery tech- to easily stored chemical energy (i.e. H2) by electrocatalytic water nologies and energy conversion process (Fig. 1). Although there splitting is of great potential, in which electrocatalysts for hydrogen are some metallic transition metal chalcogenides having similar evolution reaction (HER) and oxygen evolution reaction (OER) play properties, they are mostly metastable and easily be transformed a key role [2–5]. Then, to utilizing H2 as a clean fuel in fuel cells, oxy- to semiconducting/insulating phases [11]; hence, will not be dis- gen reduction reaction (ORR) also need to be facilitated to improve cussed in this summary. the efficiency. However, the current state-of-the-art electrocata- In this review, we mainly summarize and discuss the progress lysts for these conversion processes are still based on precious in energy storages (LIBs/SIBs and supercapacitors) and conversions metals (i.e. Pt [6] for HER, ORR and RuO2/IrO2 [7] for OER), which (HER, OER, ORR) that employ metallic like transition metal-based brutally hindered large scale applications. Hence, inexpensive and nanostructures (MLTMNs). Fundamental characteristics in terms of natural abundant alternatives with good catalytic performance and crystal structures are introduced. Then, we present comprehensive sturdiness over time are highly desired. insight and recent advances of synthesis methods, energy storage The combination of transition metals and elemental phospho- and conversion applications with attention focused on strategies rus, carbon, nitrogen, and boron give families of compounds; to promote performances of each type of metallic transition metal namely, phosphides, carbides, nitrides, and borides. Those mate- nanostructured. Lastly, we suggest our personal outlook on this rials, which exhibit significant advantages of being cheap, promising class of materials to pave the way for future stud- accessibility.