[C-5Quad]

I found some good reading about the different materials used in Li-cell building and how each changes the cell and FEPO are the most stable so far and also cheep to build so maybe a 90% off will get me to buy a few.........but really a good read for thoes interested

Figure I would post something worth reading in this thred

There’s Not One Lithium Ion BatteryCrucially, there is no one lithium-ion battery, although this mistake is often seen in the press. Several different chemical formulations for the electrodes compete; each has its pros and cons. “No chemistry will be the perfect one,” says Klaus Brandt, the chief executive of Gaia, a German cell maker. The anode (or negative electrode) is typically made of graphite, but the cathode (positive electrode) chemistry varies widely. As much as any other factor, what the cathode is made from determines the cell’s capacity. The critical feature is the rate at which the cathode can absorb and emit free lithium ions. Each of several competing cathode materials offers a different mix of cost, durability, performance, and safety. Let's take a look at the most important cathode contenders.

Cobalt Dioxide
Cobalt Dioxide is the most popular choice today for small cells (those in your mobile phone or laptop). It’s been on the market for 15 years, so it’s proven and its costs are known, though like nickel, cobalt is pricey. Cobalt is more reactive than nickel or manganese, meaning it offers high electrical potential when paired with graphite anodes, giving higher voltage. It has the highest energy density—but when fully charged, it is the most prone to oxidation (fire) caused by internal shorts. This can lead to thermal runaway, where one cell causes its neighbors to combust, igniting the whole pack almost instantly (think YouTube videos of burning laptops). Also, the internal impedance of a cobalt cell—the extent to which it “pushes back” against an alternating current—increases not just with use but with time as well. That means an unused five-year-old cobalt cell holds less energy than a brand-new one.


Cobalt dioxide cells are manufactured by dozens of Japanese, South Korean, and Chinese companies, but only Tesla Motors uses them—6,831 of them to be specific—in an electric car. Their pack uses sensors, cell isolation, and liquid cooling to ensure that any energy released if a cell shorts out can’t ignite any of its neighbors.

Nickel-cobalt-manganese (NCM)
Nickel-cobalt-manganese (NCM) is somewhat easier to make. Manganese is cheaper than cobalt, but it dissolves slightly in electrolytes—which gives it a shorter life. Substituting nickel and manganese for some of the cobalt lets manufacturers tune the cell either for higher power (voltage) or for greater energy density, though not both at the same time. NCM remains susceptible to thermal runaway, though less so than cobalt dioxide. Its long-term durability is still unclear, and nickel and manganese are both still expensive now. Manufacturers include Hitachi, Panasonic, and Sanyo.

Nickel-cobalt-aluminum (NCA)
Nickel-cobalt-aluminum (NCA) is similar to NCM, with lower-cost aluminum replacing the manganese. Companies that make NCA cells include Toyota and Johnson Controls–Saft, a joint venture between a Milwaukee automotive supplier and a French battery firm.

Manganese oxide spinel (MnO)
Manganese oxide spinel (MnO) offers higher power at a lower cost than cobalt, because its three-dimensional crystalline structure provides more surface area, permitting better ion flow between electrodes. But the drawback is a much lower energy density. GS Yuasa, LG Chem, NEC-Lamilion Energy, and Samsung offer cells with such cathodes; LG Chem is one of two companies competing to have its cells used in the Chevrolet Volt.

Iron phosphate (FePo)
Iron phosphate (FePo) might be the most promising new cathode, thanks to its stability and safety. The compound is inexpensive, and because the bonds between the iron, phosphate, and oxygen atoms are far stronger than those between cobalt and oxygen atoms, the oxygen is much harder to detach when overcharged. So if it fails, it can do so without overheating. Unfortunately, iron phosphate cells work at a lower voltage than cobalt, so more of them must be chained together to provide enough power to turn a motor. A123 Systems—which is competing for the Volt contract as well—uses nanostructures in their FePo cathodes, which it says produces better power and longer life. Other manufacturers include Gaia and Valence Technology.


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