There have been so many new approaches to batteries lately that it’s hard to keep track of them all, but most of them have one thing in common: they are all cheaper and safer than lithium-ion batteries.Listen, lithium-ion batteries are the best we’ve got on the market right now. They can store a lot of energy in a small, lightweight package — that’s why they’re in basically everything we own — but they also have some drawbacks. The materials needed to make them aren’t earth-abundant, which makes them more expensive, especially as you scale up in size. They are a fire risk and they also have a fairly short life span.For years, researchers have been looking to more abundant, safer materials to create a better battery. Engineers at South Korea’s Ulsan National Institute of Science and Technology (UNIST) are just the latest. They have developed a seawater battery that runs on water and salt, which they say could soon rival the lithium-ion battery in performance.Sodium is the sixth most abundant element on earth, making this battery far cheaper to manufacture and using seawater specifically greatly reduces any chance of fire. The researchers believe that in the future, seawater could be the key to the large-scale energy storage that’s needed as the world shifts to more renewable energy. The batteries could also be used as emergency back-up energy for homes, businesses and ships.The seawater battery works much like a lithium-ion battery as the structure is the same, swapping out lithium for sodium. The university explains:The battery extracts sodium ions from the seawater when it is charged with electrical energy and stores them within the cathode compartment. Upon electrochemical discharge, sodium is released from the anode and reacts with water and oxygen from the seawater cathode to form sodium hydroxide. This process provide energy to power, for instance, an electric vehicle.The salt water is not just acting as an electrolyte; according to the American Chemical Society newsletter it is actually a “catholyte — an electrolyte and cathode combined. In batteries, the electrolyte is the component that allows an electrical charge to flow between the cathode and anode. A constant flow of seawater into and out of the battery provides the sodium ions and water responsible for producing a charge.”Currently, the seawater batteries have a lower electrical output than lithium-ion batteries, but the researchers are working on building the batteries in various sizes and shapes to increase the charge rate. They will soon start mass producing the seawater batteries in a testing facility and join cells together in battery packs. The goal is to produce a battery pack by the end of next year that is capable of providing the home energy needs of a family of four.
Shirley Gonzales made no secret of her views on transportation when she ran for the San Antonio City Council in 2013. She laid them out in her answer to a questionnaire: “pedestrians first, followed by cycling, public transportation and private automobiles, in that order.” Gonzales promoted this agenda even though she was running in a city where fewer than 2 percent of commuters walk to work.A few months later, after she’d won the election, the tales of some of her constituents drove the issue home. Most prominent was the story of Sharon Ledesma, a 28-year-old single mother who was crossing a four-lane street one night when a car switched lanes and veered toward her and her two children. Ledesma managed to push the children out of the way. Dominic, who was 11 at the time, and Mallory, who was 8, survived but had serious injuries. Both had broken bones and were on crutches for weeks. Ledesma, however, did not make it. She was declared brain dead at the hospital. The next day, after her kids had a chance to say goodbye, her family took her off life support.Gonzales began to hear from other San Antonio families. The city had one of the highest pedestrian death rates in the country. In fact, 373 pedestrians had died in the metropolitan area over the previous decade. And Gonzales’ own district, largely poor and Hispanic, had some of the most dangerous streets, especially Culebra Road, the arterial where Ledesma died. That four-lane road shares many of the characteristics of other deadly stretches for pedestrians: Cars traveling near the speed limit of 40 mph pass between modest homes and retail outlets, while pedestrians walk along sidewalks separated from the traffic by only a low curb for as much as half a mile between crosswalks.
In the battle of cars versus raised bike lanes, the cars just won a small battle in San Francisco.The city had planned on installing a two-inch raised, mountable lane on a section of Polk Street, where, on average, cars hit one cyclist and one pedestrian every month. But now it’s scrapped that plan in favor of a more traditional lane, which will be protected with soft-hit posts.The switch comes after San Francisco evaluated its first, experimental raised lane on downtown’s Market Street. The lane proved challenging to some cyclists since it debuted in late 2015; at least two collisions occurred (one resulting in a “major injury”) when people tried to roll up onto the path. But the main issue was the raised lane just wasn’t keeping cars away, as evident in angry social-media posts about police cars and a delivery truck blocking cyclists’ right of way.The San Francisco Municipal Transportation Agency says it believes lanes in these kinds of heavily commercialized corridors should be protected with a line of parked cars (something Oakland recently did, with varying success). But since that’s not possible on Polk, it will have plastic barriers sticking up from a buffer zone, as depicted on the right:
Harvesting fog to solve a water crisis