Ming-Yao Cheng

A new graphene-modified protic ionic liquid-based composite membrane for solid polymer electrolytes

The production of a solid polymer electrolyte with high ionic conductivity and mechanical properties is the main fabrication challenge in application of polymer electrolyte membranes. This paper describes a novel polymer electrolyte membrane using protic ionic liquids (PILs) with ionic liquid polymer modified graphene (G) sheets [denoted PIL(NTFSI)-G] that exhibit dramatic enhancements in ionic conductivity (257.4%) and mechanical properties (345% improvement in tensile strength and a near 25-fold increase in modulus were achieved at 150 °C) with a minimal loading of PIL(NTFSI)-G (0.5 wt%). The addition of graphene, by sparing the high-cost PIL addition, gives a 20% cost-saving. The homogeneous distribution of graphene sheets as a 3D network through the polymer matrix in the composite membrane provides a high degree of continuous and interconnected transfer channels to facilitate ion transfer and enhance nanofiller–matrix adhesion to reinforce mechanical properties. This newly developed material provides a potential route toward the design and fabrication of polymer electrolytes.

Highly-dispersed and thermally-stable NiO nanoparticles exclusively confined in SBA-15: Blockage-free nanochannels

In this work, exclusive formation of metal oxide nanoparticles confined in ordered mesoporous supports was achieved by a hydrophobic encapsulation route illustrated with the NiO/SBA-15 system. Uniform, discrete and thermally-stable NiO nanoparticles are well-distributed in a confined space. The confined nanoparticles possessed high thermal stability, the average size only slightly increasing from 2.83 nm to 3.69 nm after treatment at 900 °C. The NiO-confined nanochannels show no blockages, even though the NiO loading is as high as 18.55 wt%. This blockage-free nanoarchitecture greatly enhances application in catalysis, as demonstrated by the methanation reaction, for which the new catalyst was ∼18.5 times as effective as conventional types.

Rapid microwave-enhanced ion exchange process for the synthesis of LiNi0.5Mn0.5O2 and its characterization as the cathode material for lithium batteries

An energy- and time-efficient microwave-enhanced ion exchange (MW-IE) process is developed for the synthesis of low-cation-mixed LiNi0.5Mn0.5O2 cathode material. The synthesized MW-IE LiNi0.5Mn0.5O2 shows comparable low cation mixing (∼ 4%) within a short reaction time of 10 min, when comparing with conventional ion exchange processes with a reaction time of 5–10 h. The MW-IE LiNi0.5Mn0.5O2 delivers a higher initial discharge capacity (213 mAh g−1) than that obtained by the sol–gel (SG) method (186 mAh g−1) when charging in the potential range of 2.5–4.6 V. Further electrochemical cycleability of MW-IE LiNi0.5Mn0.5O2 cathode demonstrates excellent capacity retention and rate capability compared to that of the SG LiNi0.5Mn0.5O2 cathode. The results show better Li+ ion pathways for MW-IE LiNi0.5Mn0.5O2, where Li+ ion transport in SG LiNi0.5Mn0.5O2 would be obstructed by transition metal cations (Ni2+, resulting from higher degree of cation mixing). The effective methodology developed could be easily extended to the synthesis of potential layered compounds with less cation-mixing.

Facile synthesis of SnO2-embedded carbon nanomaterials viaglucose-mediated oxidation of Sn particles

An unusual oxidative reaction of micron-sized Sn particles to form highly dispersed SnO2 nanoparticles, embedded in a carbon matrix, during hydrothermal treatment in glucose solution is disclosed in this study. The reaction mechanism is proposed to result from the promotion of glucose decomposition by Sn. The work also discloses a green process with a yield of 5∼10-fold higher than the commonly employed hydrothermal process. The embedded SnO2 nanoparticles are electrochemically stable for Li storage during the charging–discharging process, which suggests a promised strategy for the stabilization of Sn-based anode materials for Li-ion batteries. It also implies that the unusual oxidative reaction holds great potential for the synthesis of various nano-sized inorganic oxides embedded in carbon matrices to specific applications.

A novel synthesis of highly ordered P‐SBA‐15 mesoporous materials

Abstract A simple synthesis method is presented to prepare highly ordered novel P‐SBA‐15 materials, which can provide additional BrØnsted acid sites for potential applications in catalysis. The developed materials have been unambiguously characterized by various techniques such as SAXS, nitrogen physisorption, SEM, TEM, 31PNMR and FT‐IR spectroscopy. The SAXS and TEM results revealed well‐ordered hexagonal arrays of mesoporous materials. 31PNMR and EDS results confirmed the incorporation of phosphorous in the SB A‐15 network. The method can provide an efficient way to synthesize high phosphorous content mesoporous silica with ordered structure.