Oak Ridge National Laboratory has announced that their researchers have built and demonstrated a high-voltage (5 V) lithium, solid-state battery with a usable life of more than 10,000 cycles, at the end which test the battery retains more that 90-percent of its original capacity. That makes two such claims in a week, with ORNL’s battery comparable to that developed by Nanyang Technology University (NTU) and reported on in this blog last week. ORNL points out that, “For a given size of battery, the energy stored in a battery is proportional to its voltage. Conventional lithium-ion batteries use organic liquid electrolytes that have a maximum operating voltage of 4.3 V. Operating a battery above this limit causes short cycle life and serious safety concerns.” “In this latest study, the Oak Ridge team replaced the conventional liquid electrolyte with a ceramic solid electrolyte of lithium phosphorus oxynitride (Lipon), and used a LiNi0.5Mn1.5O4 cathode and Li anode at a charge voltage to 5.1V.” The …
“Double-Duty” Electrolyte Extends Battery Longevity
Morgan McCorkle at the Department of Energy’s Oak Ridge National Laboratory in Tennessee reports that researchers there have developed a lithium-carbon fluoride battery with a thiophosphate electrolyte that generates 26 percent higher capacity than its theoretical maximum if all the components acted independently. This serendipitous outcome causes researcher Chengdu Liang to say, “This bi-functional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with unprecedented energy density.” We’ve become accustomed to thinking that a battery’s “three main components – the positive cathode, negative anode, and ion-conducting electrolyte – can play only one role in the device.” ORNL’s battery has a specially-developed solid electrolyte that functions as an ion conductor, and also serves as a cathode supplement, boosting the cell’s capacity and extending the life of the battery. The big drawback at this time is the single-use nature of the battery – a primary unit that is not rechargeable (so far). The lithium …