Neil Spinner

Recent progress in the electrochemical conversion and utilization of CO2

Over the past several years, there has been a growing interest in the capture of carbon dioxide emissions and either their permanent immobilization or chemical conversion to industrially relevant products. Several processes have been developed and studied; however, many of these methods are quite expensive since they require either ultra high purity CO2 or are energy intensive. Also, many purely chemical methods show low product selectivity. To address these limitations, several researchers have initiated activities using electrochemical processes to increase reaction pathway selectivity and reduce cost since it allows for direct control of the surface free energy through the electrode potential, which has shown promise. This review article focuses on the advantages and disadvantages of current electrochemical, photoelectrochemical and bioelectrochemical processes for CO2 conversion, and future directions for research in this area are discussed.

Investigation of metal oxide anode degradation in lithium-ion batteries via identical-location TEM

Metal oxides are one of the most promising classes of materials to replace graphite anodes in future high energy density, high power density applications for lithium-ion batteries (LIBs), including (hybrid) electric vehicles and grid-scale energy storage. Unlike graphite, which undergoes lithium ion intercalation, nearly all metal oxides (MOs) experience structural decomposition and phase separation during charge–discharge. In this work, ordered mesoporous nickel oxide (OMNiO) was synthesized and used as a representative MO to study the nanoscale structural changes that occur during charge–discharge via identical-location transmission electron microscopy (IL-TEM). We connect IL-TEM with coin cell electrochemical studies to explain the root cause for the rapid capacity fade that is common to MOs generally, and NiO specifically. We show that the electronic conductivity, in addition to MO structure, plays a crucial role in maintaining high capacity over repeated charge–discharge cycling.

Effect of Nickel Oxide Synthesis Conditions on its Electrochemical Behavior in Alkaline Media

• To examine effects of multiple NiO synthesis methods on both physical properties and electrochemical performance through the scope of the methanol oxidation reaction. Physical properties studied using: Electrochemical properties studied using: • CV and EIS To determine an optimum synthesis method for maximum electrocatalytic activity and stability. Three aqueous-phase methods were investigated: Method A: NH 4 OH-induced reflux precipitation • 0.5M Ni(NO 3) 2 in 10M NH 4 OH solution boiled under reflux for 24hrs, then capped at room temperature for 24hrs. Precipitated precursor (Ni(OH) 2) rinsed, dried, and calcined in air at 500°C. Method B: Room temp. NaOH-induced precipitation • Finely-ground NaOH pellets gradually added to 0.5M Ni(NO 3) 2 in water at room temperature, then capped at room temperature for 24hrs. Precipitated precursor rinsed, dried, and calcined in air at 500°C. • Finely-ground NaOH pellets gradually added to 0.5M Ni(NO 3) 2 in water at the solutions boiling point, then capped at room temperature for 24hrs. Precipitated precursor rinsed, dried, and calcined in air at 500°C. Method A Method B Method C 17 140 212 NiO BET Specific Surface Areas (m 2 /g) Method A Method B Method C 42 22 31 • Average particle sizes much larger for Method A than for Methods B and C, yielding lower surface area. • Methods B and C produce spherical agglomerations; Method A maintains bladelike structure even after calcination. • High calcination temperature and times result in lower and more uniform surface areas after calcination to NiO. • All reactions irreversible; no return scan activity. • Smaller crystal size for Method B leads to 30°C decrease in calcination temperatures over Method A 4. • Narrow peaks for Method A precursor XRD pattern indicate pure, hexagonal b-Ni(OH) 2 3. • Broader peaks for Methods B and C precursors suggest: i. Smaller particles leading to greater surface areas; ii. Disordered stacking/growth faults and/or proton vacancies in the b-Ni(OH) 2 structure; iii. Less stable, amorphous or poorly crystalline, a-phase Ni(OH) 2 4. • Grain boundary trends consistent with BET data. • NiO patterns more uniform. • Method B resistances ~30% lower than Method A. • Around 85% average decrease in resistances for Na 2 CO 3 vs. KOH solutions – consistent with ~3-4x larger currents seen in CVs. • No noticeable differences in electrocatalytic activity between Method B and Method C; Method B preferred due to ease of synthesis. NiO nanoparticles fabricated …