Spectroscopic understanding of ultra-high rate performance for LiMn0.75Fe0.25PO4 nanorods–graphene hybrid in lithium ion battery

Abstract

Comprehensive X-ray absorption near-edge structure spectroscopy at the C, O and Li K-edges and the Mn, Fe, and P L-edges of LiMn(0.75)Fe(0.25)PO(4) nanorods-graphene has been reported in great detail. Compared to that of free standing graphene and LiMn(0.75)Fe(0.25)PO(4), the intimate interaction between the nanorods and graphene via charge redistribution has been unambiguously confirmed. This interaction not only anchors the nanorods onto the graphene but also modifies its surface chemistry, both of which afford the nanorods-graphene hybrid an ultra-high rate performance in lithium ion batteries. Such knowledge is important for the understanding of hybrid nanomaterials for lithium ion batteries and allows rational design for further improvements in performance.

Enhancing Solar‐Driven Water Splitting with Surface‐Engineered Nanostructures

“…This clearly reveals chemical interaction between α‐Fe 2 O 3 and TiO 2 , which likely promotes charge transfer from the Fe(3 d ) state to the Ti(3 d ) state via the interfacial Fe‐O‐Ti bonding. Similar change in Fe L ‐edge spectrum has been observed in graphene‐coated LiMnFePO 4 lithium ion cathode materials . Increasing hybridization could lead to increased oxygen electrocatalysis, which should benefit the PEC water splitting performance of α‐Fe 2 O 3 nanorod films with surface engineered with a TiO 2 overlayer, as also measured by the XANES in dark and under light illumination.…”

In SituX-ray Absorption Near-Edge Structure Study of Advanced NiFe(OH)xElectrocatalyst on Carbon Paper for Water Oxidation

“…Peak A centered at 527.7 eV is attributed to the hybridization of O 2p and metal 3d orbitals; peak B is assigned to the multiple scattering of p wave in the first oxygen shell, and the peak between A and B is assigned to the hybridization of O 2p character with Ni 3d states (proportional to unoccupied density of states). 69 It can be seen that after incorporation of Fe into Ni hydroxides the electronic structure of O have been greatly altered. A small but reproducible blue-shift at peak B for catalyst relative to that of the Ni hydroxide is distinguished, suggesting a shortened Ni−O bond caused by Fe doping.…”

Synchrotron Soft X‐ray Absorption Spectroscopy Study of Carbon and Silicon Nanostructures for Energy Applications

“…Such anchoring was reported to be very important for the excellent performance of nanomaterial‐rGO hybrids due to the synergetic effects . XANES was thus used to probe the interfacial interaction between LMFP and rGO . Recently, XANES spectra at the C, O and Li K ‐edges and Mn, Fe, and P L ‐edges of LiMn 0.75 Fe 0.25 PO 4 nanorod‐rGO hybrid were measured with abundant structural information .…”

“…XANES was thus used to probe the interfacial interaction between LMFP and rGO . Recently, XANES spectra at the C, O and Li K ‐edges and Mn, Fe, and P L ‐edges of LiMn 0.75 Fe 0.25 PO 4 nanorod‐rGO hybrid were measured with abundant structural information . XANES data suggested that it was the PO 4 unit in LMFP which bonded to rGO, which showed an enhanced feature at about 288 eV in the C K ‐edge XANES spectra .…”

“…Recently, XANES spectra at the C, O and Li K ‐edges and Mn, Fe, and P L ‐edges of LiMn 0.75 Fe 0.25 PO 4 nanorod‐rGO hybrid were measured with abundant structural information . XANES data suggested that it was the PO 4 unit in LMFP which bonded to rGO, which showed an enhanced feature at about 288 eV in the C K ‐edge XANES spectra . The bonding might weaken the P‐O covalent bond in LMFP and thus strengthen the Fe–O covalent bonds.…”