The limiting factor in the usability and popularity of clean, electric-powered leaf blowers is the same as the limiting factor in the cost and range of Teslas and other electric cars, or of a new generation of battery-powered airplanes, or even of the spread of solar and wind power systems that need batteries to store power when it's sunny or wind, to use when it is dark or calm.
That factor is the performance and cost of batteries. Through the past decade, innovation (driven mainly by the mobile-phone and other consumer-electronics industry) has made batteries ever cheaper, ever lighter, and ever longer-duration. Now a Wall Street Journal story says that a significant step up is at hand.
The entire story by Christopher Mims is worth reading. Some highlights:
The batteries that power our modern world—from phones to drones to electric cars—will soon experience something not heard of in years: Their capacity to store electricity will jump by double-digit percentages, according to researchers, developers and manufacturers.
The next wave of batteries, long in the pipeline, is ready for commercialization. This will mean, among other things, phones with 10% to 30% more battery life, or phones with the same battery life but faster and lighter or with brighter screens.... As this technology becomes widespread, makers of electric vehicles [and lawn equipment] and home storage batteries will be able to knock thousands of dollars off their prices over the next five to 10 years.
The technical advance, carefully spelled out in the story, involves a move from graphite to silicon as a main component in the battery. Brief summary:
Typically, anodes in lithium-ion batteries are made of graphite, which is carbon in a crystalline form. While graphite anodes hold a substantial number of lithium ions, researchers have long known a different material, silicon, can hold 25 times as many.
For more, please see Mims's article. The big picture, once again, is that the dirty, noisy gas-powered equipment found on many lawns is a rare remnant of very old technology. What is rushing to replace it is part of a sweeping new material-science revolution in power storage.