Electrochemical and ex-situ analysis on manganese oxide/graphene hybrid anode for lithium rechargeable batteries
- PDF / 413,215 Bytes
- 7 Pages / 584.957 x 782.986 pts Page_size
- 96 Downloads / 222 Views
Sung-Wook Kim Research Institute of Advanced Materials, Seoul National University, Seoul 151-742, Republic of Korea
Jihyun Hong, Young-Uk Park, and Kisuk Kanga) Department of Materials Science and Engineering, Seoul National University, Seoul 151-742, Republic of Korea (Received 23 May 2011; accepted 19 August 2011)
A Mn3O4/graphene hybrid material is fabricated using a facile and simple in-situ reduction process and shown to be a promising anode for lithium rechargeable batteries. The hybrid material retains a high capacity with a good cycle life of up to 990 mAh g1 after 30 cycles. The excellent electrochemical performance is attributable to the unique nanostructure of the hybrid material. Highly crystalline Mn3O4 particles (20–30 nm) are uniformly dispersed on graphene whose high electronic conductivity and high surface area provide a conductive percolating network throughout the electrode in the hybrid material. The conductive graphene networks enhance an electron transfer in the electrode and promote the electrochemical activity of the crystalline Mn3O4.
I. INTRODUCTION
Reliable energy storage devices are needed to satisfy increasing demands in the fields of electronics, vehicles, and renewable energy generation systems, and lithium (Li) rechargeable batteries are promising candidates for these applications due to their high level of energy and power density.1 Intensive research efforts are currently focused on enhancing energy and power density of Li rechargeable batteries by exploring new electrode materials. Graphite is the most widely used anode for Li rechargeable batteries. However, its relatively low capacity, 372 mAh g1, presents challenges for new applications in Li rechargeable batteries. Thus, much research has focused on developing next generation anode materials with higher levels of energy and power density than graphite-based anodes.2–9 Of particular interests among these studies have been those that have focused on conversion reaction compounds such as cobalt oxides, copper oxides, and nickel oxides due to their high theoretical capacity.5,8–16 Because simple metal oxides can react with more than one Li ion through conversion reaction, these compounds can exhibit high capacity.17 CoO and Co3O4, typical conversion reaction compounds, have been extensively studied due to their high theoretical capacities of ;720 and 900 mAh g1, respectively.8–12,18 However, toxicity and expensive production cost of cobalt-containing materials are major obstacles for commercialization.9,19,20 Thus, attention has shifted
a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2011.301 J. Mater. Res., Vol. 26, No. 20, Oct 28, 2011
http://journals.cambridge.org
Downloaded: 14 Mar 2015
toward lower cost transition metal-containing materials such as MnO, Mn2O3, and Mn3O4.19–24 Although Mn3O4 can exhibit high capacity through conversion reactions similar to Co3O4,19,20,22 its intrinsically low electronic conductivity remains an obstacle for applications in Li rechargeable bat
Data Loading...
