World’s most efficient lithium-sulfur battery

World’s most efficient lithium-sulfur battery

Summery:

Researchers are on the brink of commercializing the world’s most efficient lithium-sulfur (Li-S) battery, which could outperform current market leaders by more than four times.

Imagine having access to a battery, which has the potential to power your phone for five continuous days, or enable an electric vehicle to drive more than 1000km without needing to “refuel.”

Monash University researchers are on the brink of commercialising the world’s most efficient lithium-sulphur (Li-S) battery, which could outperform current market leaders by more than four times, and power Australia and other global markets well into the future.

Dr Mahdokht Shaibani from Monash University’s Department of Mechanical and Aerospace Engineering led an international research team that developed an ultra-high capacity Li-S battery that has better performance and less environmental impact than current lithium-ion products.

The researchers have an approved filed patent (PCT/AU 2019/051239) for their manufacturing process, and prototype cells have been successfully fabricated by German R&D partners Fraunhofer Institute for Material and Beam Technology.

Some of the world’s largest manufacturers of lithium batteries in China and Europe have expressed interest in upscaling production, with further testing to take place in Australia in early 2020.

The study was published in Science Advances on Saturday, 4 January 2020.

Professor Mainak Majumder said this development was a breakthrough for Australian industry and could transform the way phones, cars, computers and solar grids are manufactured in the future.

“Successful fabrication and implementation of Li-S batteries in cars and grids will capture a more significant part of the estimated $213 billion value chain of Australian lithium, and will revolutionise the Australian vehicle market and provide all Australians with a cleaner and more reliable energy market,” Professor Majumder said.

“Our research team has received more than $2.5 million in funding from government and international industry partners to trial this battery technology in cars and grids from this year, which we’re most excited about.”

Using the same materials in standard lithium-ion batteries, researchers reconfigured the design of sulphur cathodes so they could accommodate higher stress loads without a drop in overall capacity or performance.

Inspired by unique bridging architecture first recorded in processing detergent powders in the 1970s, the team engineered a method that created bonds between particles to accommodate stress and deliver a level of stability not seen in any battery to date.

Attractive performance, along with lower manufacturing costs, abundant supply of material, ease of processing and reduced environmental footprint make this new battery design attractive for future real-world applications, according to Associate Professor Matthew Hill.

“This approach not only favours high performance metrics and long cycle life, but is also simple and extremely low-cost to manufacture, using water-based processes, and can lead to significant reductions in environmentally hazardous waste,” Associate Professor Hill said.

https://www.sciencedaily.com/releases/2020/01/200103141043.htm

Solar power from ‘the dark side’ unlocked by a new formula:

Engineers calculate the ultimate potential of next-generation solar panels

Date: December 18, 2019
Source: Purdue University
Summary:
Most of today’s solar panels capture sunlight and convert it to electricity only from the side facing the sky. If the dark underside of a solar panel could also convert sunlight reflected off the ground, even more electricity might be generated.

Most of today’s solar panels capture sunlight and convert it to electricity only from the side facing the sky. If the dark underside of a solar panel could also convert sunlight reflected off the ground, even more electricity might be generated.

Double-sided solar cells are already enabling panels to sit vertically on land or rooftops and even horizontally as the canopy of a gas station, but it hasn’t been known exactly how much electricity these panels could ultimately generate or the money they could save.

A new thermodynamic formula reveals that the bifacial cells making up double-sided panels generate on average 15% to 20% more sunlight to electricity than the monofacial cells of today’s one-sided solar panels, taking into consideration different terrain such as grass, sand, concrete and dirt.

The formula, developed by two Purdue University physicists, can be used for calculating in minutes the most electricity that bifacial solar cells could generate in a variety of environments, as defined by a thermodynamic limit.

“The formula involves just a simple triangle, but distilling the extremely complicated physics problem to this elegantly simple formulation required years of modeling and research. This triangle will help companies make better decisions on investments in next-generation solar cells and figure out how to design them to be more efficient,” said Muhammad “Ashraf” Alam, Purdue’s Jai N. Gupta Professor of Electrical and Computer Engineering.

In a paper published in the Proceedings of the National Academy of Sciences, Alam and coauthor Ryyan Khan, now an assistant professor at East West University in Bangladesh, also show how the formula can be used to calculate the thermodynamic limits of all solar cells developed in the last 50 years. These results can be generalized to technology likely to be developed over the next 20 to 30 years.

The hope is that these calculations would help solar farms to take full advantage of bifacial cells earlier in their use.

“It took almost 50 years for monofacial cells to show up in the field in a cost-effective way,” Alam said. “The technology has been remarkably successful, but we know now that we can’t significantly increase their efficiency anymore or reduce the cost. Our formula will guide and accelerate the development of bifacial technology on a faster time scale.”

The paper might have gotten the math settled just in time: experts estimate that by 2030, bifacial solar cells will account for nearly half of the market share for solar panels worldwide.

Alam’s approach is called the “Shockley-Queisser triangle,” since it builds upon predictions made by researchers William Shockley and Hans-Joachim Queisser on the maximum theoretical efficiency of a monofacial solar cell. This maximum point, or the thermodynamic limit, can be identified on a downward sloping line graph that forms a triangle shape.

The formula shows that the efficiency gain of bifacial solar cells increases with light reflected from a surface. Significantly more power would be converted from light reflected off of concrete, for example, compared to a surface with vegetation.

The researchers use the formula to recommend better bifacial designs for panels on farmland and the windows of buildings in densely-populated cities. Transparent, double-sided panels allow solar power to be generated on farmland without casting shadows that would block crop production. Meanwhile, creating bifacial windows for buildings would help cities to use more renewable energy.

The paper also recommends ways to maximize the potential of bifacial cells by manipulating the number of boundaries between semiconductor materials, called junctions, that facilitate the flow of electricity. Bifacial cells with single junctions provide the largest efficiency gain relative to monofacial cells.

“The relative gain is small, but the absolute gain is significant. You lose the initial relative benefit as you increase the number of junctions, but the absolute gain continues to rise,” Khan said.

The formula, detailed in the paper, has been thoroughly validated and is ready for companies to use as they decide how to design bifacial cells.

This research was partially supported by the National Science Foundation under award 1724728.

https://www.sciencedaily.com/releases/2019/12/191218153556.htm

WHAT IS SMOG

It is type of air pollution and basically is a mixture of Smoke and fog in the air. Intensity smog is more where emissions of Burning of fossil fuels and anthropogenic are in larger amount

How smog is formed?

Visible air pollution consists of Sulphur Oxide, Nitrogen oxide and other particles. Anthropogenic smog is raised from coal combustion emissions, vehicular emissions, industrial emissions, stack emissions, forest and agricultural fires and photochemical reactions of these emissions. When sunlight and its heat react with these emission and fine particles in the atmosphere, smog is formed.

Effects of Smog on Human health

The ground level ozone present in the smog also inhibits plant growth and causes immense damage to crops and forests. Crops, vegetables like soybeans, wheat, tomatoes, peanuts, and cotton are subject to infection when they are exposed to smog. The smog results in mortifying impacts on the environment by killing innumerable animal species and green life as these take time to adapt to breathing and surviving in such toxic environments.

Smog formation time depends on the temperature. Temperature inversions are situations when warm air does not rise instead stays near the ground. During situations of temperature inversions, if the wind is calm, smog may get trapped and remain over a place for days. Smog is more severe when it occurs farther away from the sources of release of pollutants. The reason behind is that photochemical reactions that causes smog to take place in the air when the released pollutants from heavy traffic drift due to the wind. Smog can thus affect and prove to be dangerous for suburbs, rural areas as well as urban areas or large cities. Smog is often caused by heavy traffic, high temperatures, sunshine, and calm winds. These are a few of the factors behind an increasing level of air pollution in the atmosphere.

During the winter months when the wind speeds are low, it helps the smoke and fog to become stagnate at a place forming smog and increasing pollution levels near the ground closer to where people are respiring. It hampers visibility and disturbs the environment. Smog is a disturbing problem particularly due to the fast modernization or industrialization as the dangerous chemicals involved in smog formation are highly reactive is supper around in the atmosphere. Smoke and sulfur dioxide pollution in urban areas is at much lower levels than in the past, as a result of the law passed to control emissions and in favor of cleaner emission technology.

Impact of smog can be reduced by applying alterations in your standard of living, declining the depletion of fuels that are non-renewable and by substituting them with alternate sources of fuel which will reduce toxic emissions from vehicles.

 Deaerator

Introduction

Deaerator is basically used to eliminate air and other gases from the liquid. For example, from feed water being used in steam generating boilers. The oxygen which is dissolved in the feed water is very dangerous for the boiler as it may cause corrosion in the boiler by reacting with metal of the walls of the boiler.

Purpose

In Power Plants where boiler is working for production of steam from boiler feed water. Deaerator resolves the purpose of removal of undesirable dissolved gases and dissolved oxygen from the boiler feed water before entering boilers. Deaerator are designed in such a way that the dissolved oxygen content in the outlet water is about 7 ppb by wt.%.

Deaerator Principle

Deaerator works on the Henry’s law and inverse solubility of water.

  1. Inverse Solubility of water.

When the temperature of water is increased, the dissolved oxygen content in the water is decreases. Therefore, the water temperature is increased by adding steam in Deaerator, the dissolved gas solubility is decreased, and the gases are removed from water

  1. Henry’s law

The solubility of the gas in a liquid is directly proportional to the partial pressure. Therefore, if we decrease the partial pressure of the dissolved gas by adding steam in Deaerator, its solubility decreases, and the gas is removed from water.

  • Types of Deaerator
  1. Spray type Deaerator:

In Spray type Deaerator the Pre-deaeration of feed water sprayed in the steam space and the feed water is contacted with the steam deaeration happens. The pre-deaeration is attained by the Stork spraying device. With due operating environment the sprayer assures heating of the condensate to saturation temperature and a very large area for mass transfer. The solubility of oxygen in water at saturation conditions is practically zero, while oxygen transfers from the water droplets to the surrounding steam. As the steam condensates on the water, the concentration of oxygen in the direct vicinity of the sprayer is increased making it possible to vent a small amount of steam with high oxygen concentration.

  1. Tray type Deaerator:

A tray type Deaerator with a vertical domed Deaerator section pointed abve a horizontal boiler feed water storage cylinder. Feed water walks into the vertical deaeration section above the perforated trays and flows downward through the perforations. The low-pressure deaeration steam enters below the perforated trays and flows upward through the perforations and had a good contact with the feed water. The steam strips the dissolved gas from the boiler feed water and exits via the vent at the top of the domed section. The Deaerated water flows down into the horizontal storage vessel from where it is pumped to the steam generating boiler system. Low-pressure heating steam, which enters the horizontal vessel through a sprayer pipe in the bottom of the vessel, provided to keep the stored boiler feed water warm

 

  1. Vacuum type Deaerator

It contain  three main parts, 1).vacuum Deaerator,2).vacuum pump unit and 3).boiler feed water pump. Deaeration tank is made by galvanized or SS. There is inside bottom inside the tank, under which a reservoir for Deaerated water is mounted. Filters are on the top of the bottom. A vacuum pump/liquid ring pump is connected with the Deaerator for sucking the progressive dissolved gasses. A negative pressure is maintained in the Deaerator system to increase the liberation of dissolved gasses from the boiler feed water.

  • Construction of Deaerator:

Deaerator is always constructed on height from the pump to maintain optimum pressure before suction and the heater after the Deaerator are known as low pressure heaters.