Rizwan Raza

A new energy conversion technology joining electrochemical and physical principles

We report a new energy conversion technology joining electrochemical and physical principles. This technology can realize the fuel cell function but built on a different scientific principle. The d ...

Direct biofuel low-temperature solid oxide fuel cells

A low-temperature solid oxide fuel cell system was developed to use bioethanol and glycerol as fuels directly. This system achieved a maximum power density of 215 mW cm−2 by using glycerol at 580 °C and produced a great impact on sustainable energy and the environment.

Preparation and characterization of Sm and Ca co-doped ceria–La0.6Sr0.4Co0.2Fe0.8O3−δ semiconductor–ionic composites for electrolyte-layer-free fuel cells

A series of Sm and Ca co-doped ceria, i.e. Ca0.04Ce0.96-xSmxO2-delta (x = 0, 0.09, 0.16, and 0.24) (SCDC), were synthesized by a co-precipitation method. Detailed morphology, composition, crystal s ...

Advanced electrolyte-free fuel cells based on functional nanocomposites of a single porous component : analysis, modeling and validation

Recently, a fuel cell device constructed with only one layer composited of ceria-based nanocomposites (typically, lithium nickel oxide and gadolinium doped ceria (LiNiO2–GDC) composite materials), called an electrolyte-free fuel cell (EFFC), was realized for energy conversion by Zhu et al. The maxium power density of this single-component fuel cell is 450 mW cm−2 at 550 °C when using hydrogen fuel. In this study, a model was developed to evaluate the performance of an EFFC. The kinetics of anodic and cathodic reactions were modeled based on electrochemical impedance spectroscopy (EIS) measurements. The results show that both of the anodic and cathodic reactions are kinetically fast processes at 500 °C. Safety issues of an EFFC using oxidant and fuels at the same time without a gas-tight separator were analyzed under open circuit and normal operation states, respectively. The reaction depth of anodic and cathodic processes dominated the competition between surface electrochemical and gas-phase reactions which were effected by the catalytic activity and porosity of the materials. The voltage and power output of an EFFC were calculated based on the model and compared with the experimental results.

Direct lignin fuel cell for power generation

Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for direct conversion into electricity using direct carbon fuel cells (DCFC). Two different types of industrial lignins were investigated: Lignosulfonate (LS) and Kraft lignin (KL), in their commercial forms, after their blending with commercial active carbon (AC) or after alteration of their structures by a pH adjustment to pH 10. It was found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43–57 to 83–101 mA cm−2. The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.68–0.69 V and a maximum current density of 74–79 mA cm−2 from both lignins. Typical power density was 12 (for KL + AC) and 24 mW cm−2 (for LS + AC). It is concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

Significance enhancement in the conductivity of core shell nanocomposite electrolytes

Today, there is great demand of electrolytes with high ionic conductivities at low operating temperatures for solid-oxide fuel cells. Therefore, a co-doped technique was used to synthesize a highly ionically conductive two phase nanocomposite electrolyte Sr/Sm–ceria–carbonate by a co-precipitation method. A significant increase in conductivity was measured in this co-doped Sr/Sm–ceria–carbonate electrolyte at 550 °C as compared to the more commonly studied samarium doped ceria. The fuel cell power density was 900 mW cm−2 at low temperature (400–580 °C). The composite electrolyte was found to have homogenous morphology with a core–shell structure using SEM and TEM. The two phase core–shell structure was confirmed using XRD analysis. The crystallite size was found to be 30–60 nm and is in good agreement with the SEM analysis. The thermal analysis was determined with DSC. The enhancement in conductivity is due to two effects; co-doping of Sr in samarium doped ceria and its composite with carbonate which is responsible for the core–shell structure. This co-doped approach with the second phase gives promise in addressing the challenge to lower the operating temperature of solid oxide fuel cells (SOFC).

Preparation and Characterization of Nanocomposite Calcium Doped Ceria Electrolyte With Alkali Carbonates (NK-CDC) for SOFC

The entire worlds challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be ...

The energy crisis in Pakistan: A possible solution via biomass-based waste

Developing countries like Pakistan need a continuous supply of clean and cheap energy. It is a very common fear in todays world that the fossil fuels will be depleted soon and the cost of energy is increasing day-by-day. Renewable energy sources and technologies have the potential to provide solutions to long-standing energy problems faced by developing countries. Currently, Pakistan is experiencing a critical energy crisis and renewable energy resources can be the best alternatives for quickly terminating the need for fossil fuels. The renewable energy sources such as solar energy, wind energy, and biomass energy combined with fuel cell technology can be used to overcome the energy shortage in Pakistan. Biomass is a promising renewable energy source and is gaining more interest because it produces a similar type of fuel like crude oil and natural gas. Energy from biomass only depends upon the availability of raw materials; therefore, biomass can play an important role to fulfill the energy requirements ...

High performance of SDC and GDC core shell type composite electrolytes using methane as a fuel for low temperature SOFC

Nanocomposites Samarium doped Ceria (SDC), Gadolinium doped Ceria (GDC), core shell SDC amorphous Na2CO3 (SDCC) and GDC amorphous Na2CO3 (GDCC) were synthesized using co-precipitation method and then compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs). The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC) and dual phase core shell (SDCC, GDCC) electrolyte materials. EDX analysis validated the presence of Sm and Gd in both single and dual phase electrolyte materials; also confirming the presence of amorphous Na2CO3 in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core sh...

Characterization and Development of Bio-Ethanol Solid Oxide Fuel Cell

Bio-ethanol based fuel cell is an energy source with a promising future. The low temperature solid oxide fuel cell fed by direct bio-ethanol is receiving considerable attention as a clean and highly efficient for the production of both electricity and high grade waste heat. The comparison of fuel cell performance with different metal-oxide based electrodes was investigated. The power densities of 584 mW cm(-2) and 514 mW cm(-2) at 520 degrees C and 570 degrees C respectively were found. The effect of electrode catalyst function, ethanol concentration on the electrical performance was investigated at different temperature ranged in between 300 degrees C-600 degrees C. The effect of deposited carbon on the electrode was investigated by energy-dispersive X-ray spectroscopy and scanning electron microscope after testing the cell with bio-ethanol.