Material Advancements in Lithium-ion Battery Technology
Updated: May 14, 2020
A battery can get as good as the material it’s made up of. Batteries have become lighter and more energy-denser over the years because manufacturers have managed to increase the concentration of active components (electrodes) and reduce unnecessary passive components.
There are different types of battery technologies existing in the market but when comes to market share lithium-ion battery is the undisputed winner. There is often a trade-off between high energy density and cycle life. An ideal battery cell should have electrodes which could be able to accommodate huge number of lithium ions in them (high energy-density) and their structure could be able to allow lithium ions to go in and out of the material without compromising the structural integrity of the material (high cycle life).
Most families of lithium-ion battery technology use layered transition metal electrodes, most commercial being NMC 811 (each digit represents the ratio of nickel, manganese, and cobalt, respectively, in the mix) which goes through severe mechanical degradation during charging/discharging cycles. One possibility of improving the cycle life of the lithium-ion battery is by substituting layered electrodes with something structurally stronger. For instance, the 100-year-old Swiss battery company Leclanché is developing a technology that uses lithium iron phosphate (LFP), which has an “olivine” structure, as the cathode, and lithium titanate oxide (LTO), which has a “spinel” structure, as the anode. These structures are better at handling the flow of lithium ions in and out of the material .
Traditionally most of the focus has been on the cathode side and anode side has been neglected. But recently researchers are trying to replace graphite as a traditional anode with something better like silicon and lithium. For instance, Silicon does way better job at absorbing lithium ions than graphite but it goes through severe volume expansion which keeps away silicon from being commercially adopted as an alternate to graphite. Development of new anode materials with higher Lithium-intercalation capacities to replace present carbon anodes (graphite) with inherently low theoretical lithium intercalation capacities to improve the overall capacity of the battery in indispensable.
The other important thing is electrolyte which acts as a pathway for lithium ions between the electrodes. Unfortunately the liquid compounds which are good at transporting lithium ions can catch fire at low temperatures. One solution is to use solid electrolytes. But that means other compromises. It’s much harder to transfer anything from solids. Safer polymer electrolytes could be an alternative to the high flammable organic liquid electrolytes.
Battery technology has already disrupted the way we consume power today, but there’s a lot more that could be disrupted, only if we could engineer lighter, more powerful, and more energy-dense batteries. However, such high-capacity configurations must also comply with customer demands such as safety and affordability.