▎ 摘　　要

Wide differences in the structural features of graphenic carbon, especially in the case of reduced graphene oxides (rGO), are expected to have considerable impacts on the properties, thus leading to significant scatter and poor understanding/prediction of their performances for various applications, including as electrode materials for electrochemical Li-storage. In this context, the present work develops a comprehensive understanding (via thorough experimentation, including in situ X-ray diffraction studies, and analysis) on the effects of graphene oxide (GO) reduction methods/conditions on the structural features (mainly 'graphenic' ordering) and concomitant influences of the same on electrochemical Li-storage behavior. 'Moderately oxidized' GO (O/C similar to 0.41) was reduced via three different methods, viz., (i) using hydrazine hydrate vapor at room temperature (rGO-H; O/C similar to 0.23), (ii) thermal reduction by annealing at just 500 degrees C (rGO-A; O/C similar to 0.20) and (iii) hydrazine treatment, followed by the same annealing treatment (rGO-HA; O/C similar to 0.17). Raman spectroscopy, in situ X-ray diffraction recorded during annealing and high resolution TEM imaging indicate that while GO and rGO-H had considerable defect contents [I(D)/I(G) similar to 1.4 for rGO-H], including a very non-uniform interlayer spacing (varying between 3.1 and 3.6 angstrom), the 500 degrees C annealed rGO-A and rGO-HA had significantly reduced defect contents [I(D)/I(G) similar to 0.6] and near-perfect 'graphenic' ordering with a uniform interlayer spacing of similar to 3.35 angstrom. Despite the nano-scaled dimensions, defect structures, especially the non-uniform interlayer spacing, resulted in relatively poor reversible Li-capacity and rate capability for the non-annealed rGO-H, even in comparison to the bulk graphitic carbon. By contrast, the annealed rGOs, especially the rGO-HA, not only possessed a superior reversible Li-capacity of similar to 450 mA h g(-1) (at C/20), but also exhibited a significantly improved rate capability (even compared to most rGOs reported in the literature), retaining similar to 120 mA h g(-1) along with flat potential profile (below similar to 0.2 V against Li/Li+) even at 10C (as possibly never reported before with graphitic/graphenic carbons).