China has become the top country for cleantech investment, outstripping the U.S., according to a report from Ernst & Young. China’s renewable energy investment dollars outdoes the U.S. nearly two to one, Green Chip Stocks reports, and installed wind power capcity in the U.S. has dropped to its lowest in three years. Germany, India, the U.K., Portugal and Spain also topped the list. Read the full report here.

Large-scale solar plant builder BrightSource could go public within three years, GigaOm reports, citing a report from Next Up research. (The report isn’t available online.) The story notes that an IPO would still be a few years off, thanks to the reluctance of venture capitalists to invest in solar — one example being Solyndra’s axed public offering plans. But BrightSource seems to be headed in the IPO direction: it recently won a federal loan guarantee and raised $439 million in its last round of financing.

GM, Itochu charge up battery startup Sakti3 with $4.2 million, with GM reportedly proffering $3.2 million of that total. Sakti3 is working on a smaller, cheaper lithium-ion battery that could extend the range of electric vehicles currently on the market. A GM spokeswoman says it’s years away from commercialization, but the technology could eventually wind up in GM’s trucks and cars.

Come launch time in December, the Nissan Leaf will have an edge over the Chevrolet Volt thanks to sweeter state rebate policies – states like California and Tennessee are giving Leaf buyers additional incentives, but shutting out the Volt. We’ve reported before that the Volt got the short shrift from the state of California, which wouldn’t extend single drivers of the Volt access to the HOV lane (though that perk was granted to Prius owners), and also won’t give it the $5,000 rebate it’s giving the Nissan Leaf, since the Volt will have tailpipe emissions (the gas tank kicks in after the electric battery’s 40-mile range runs out), whereas the Leaf is all-electric.

Fire and ice: SunPower and Ice Energy will team up to build a pilot energy storage project, reportedly for Target. The system will use SunPower’s rooftop solar panels to generate power. When the sun wanes, Ice Energy’s ice-based storage system will take over, using power stored from the day to cool the building and cutting peak-time energy costs.

Audi may have blundered in naming its electric cars e-Tron – the French word, étron, essentially means “dung,” says Green Car Reports. If that’s the case, then it’s even more unfortunate that e-Tron is slated to present at the Paris Motor Show next month.

Tags: battery, China, e-Tron, electric cars, electric vehicles, Leaf, lithium-ion batteries, solar energy, Volt

Companies: Audi, BrightSource, Chevrolet, Ernst & Young, GM, Ice Energy, Itochu, Next Up, Nissan, Sakti3, Solyndra, SunPower, Target

The Stanford group has created a prototype lithium-sulfide cathode that forms the partner electrode to an earlier anode developed in 2007. The non-metallic form of lithium avoids a safety issue where the lithium metal can grow branchlike structures that penetrate the polymer layer which keeps the battery's two electrodes apart. Such incidents can lead to short circuits and possible explosions.

Each of the lithium-sulfide electrodes can also hold 10 times as much charge as regular lithium-ion (Li-ion) batteries, but a lithium-sulfur battery wouldn't have 10 times the energy storage capacity, because it has lower conductivity than the lithium metals in conventional batteries.

The current prototype lithium-sulfur battery managed an 80 percent increase in energy density compared to current li-ion batteries on the market, and could eventually achieve an energy density four times greater.

But a huge problem remains in making the lithium-sulfur battery's lifetime comparable to that of li-ion batteries. The prototypes lose one-third of their energy storage capacity after just five discharge and recharge cycles, and stop working completely after 40 to 50 cycles. That's because of polysulfide chemicals that dissolve into the battery's liquid electrolyte and interfere with charging and discharging.

Technology Review noted two possible solutions, including electrolyte additives that protect the electrodes or membranes that keep the polysulfides contained. But for now, consumers can look forward to nanotube-coated paper batteries from the same Stanford group.

[via Technology Review]