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This content will become publicly available on February 10, 2017

Title: Solvent-directed Solgel Assembly of 3-dimensional Graphene-tented Metal Oxides and Strong Synergistic Disparities in Lithium Storage

The graphene/metal oxide (GMO) nanocomposites promise a broad range of utilities for lithium ion batteries (LIBs), pseudocapacitors, catalysts, and sensors. When applied as anodes for LIBs, GMOs often exhibit high capacity, improved rate capability and cycling performance. Numerous studies have attributed these favorable properties to the charisma of graphene in assisting various metal oxides (MOs) to achieve near-theoretical capacities, exploiting the exceptional electronic and mechanical properties of graphene. By comparison, the true lithium storage mechanisms of graphene and their correlations with MOs remain enigmatic. Via a unique two-step liquid-flow-guided solgel process, we have synthesized and investigated the electrochemical performance of several representative GMOs, namely Fe2O3/graphene, SnO2/graphene, and TiO2/graphene. We observe that MOs play an equally important role in promoting graphene to achieve large reversible lithium storage capacity. Our experiments suggest that the unexpected lithium storage heightening may arise from a unique surface coverage mechanism of MOs. The magnitude of capacity improvement is found to scale crudely with the surface coverage of MOs but depend strongly upon the storage mechanisms of MOs variety. Importantly, synergistic effect is only observed in conversion reaction GMOs (i.e., Fe2O3/graphene and SnO2/graphene) but not in intercalationbased GMOs (i.e., TiO2/graphene). Our first principles calculations suggest an alternativemore » lithium storage sites from resultant interfaces between Li2O and graphene that agree with our experimental observations. This unusually beneficial role of MOs to graphene suggests an effective pathway for reversible lithium storage in graphene and shifts design paradigms for graphene-based electrodes.« less
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [4] ;  [5] ;  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arizona State Univ., Tempe, AZ (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  4. Arizona State Univ., Tempe, AZ (United States)
  5. Rice Univ., Houston, TX (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 2050-7488
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 4; Journal ID: ISSN 2050-7488
Royal Society of Chemistry
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States