Extending the Life of Lithium-Based Batteries Via Metal-Oxide Nanoparticles Addition

Due to the need to reduce environmental pollution and reduce the use of fossil fuels, the whole world is moving towards increasing the use of electric vehicles that will be charged from renewable energies – sun and wind. 

Lithium batteries are currently used as the main source of energy for electric vehicles. The challenges that slow down their introduction to the market are high price and low energy, that limits their driving range. 
Today, the optimal energy content is about 250 [Wh/kg] and about 700 [Wh/L] of battery. The commercial batteries are made of a graphite anode, a cathode of transition metal oxides and a nonaqueous electrolyte (Fig.1). 
wide research is being done with the aim of reducing the weight and volume of batteries, making them cheaper, with higher energy density, while extending their life span.
About fifty years ago extensive research and development of metallic lithium anode batteries (LMB) was done (Fig.1). The idea was abandoned due to issues of too short lifespan and poor safety. Recently, due to the need to reduce weight and physical size, there is a renaissance for these batteries. 

One particularly interesting technology is anode-free Li-metal battery (AFLMB) (Fig.1), which is assembled in a discharged state, without an anode at all. it contains only a sheet (foil) of thin copper as an anodic current collector. In this configuration, Li is being deposited on the surface of the current collector and dissolves during discharge. The main challenge with these batteries is its poor cyclability due to “dead-Li” formation and electrolyte continues consumption, which is strongly related to the properties of the solid electrolyte interphase (SEI), forming between the solid electrode and the liquid electrolyte during the first charge of the battery. The SEI layer was discovered by Prof. Emanuel Peled in 1979, and it is intensely investigated all over the world since then. 

We recently found that by slightly changing the electrolyte- addition of low concentration (about one percent) of metal-oxide nanoparticles (MONPs) to the electrolyte, it is possible to increase the number of cycles of an AFLMB by a factor of four, which is the highest found in the literature, and of a LMB by a factor of two. Positive effect was also found on the lifespan of a silicon anode-based battery. 
We found that MONPs addition improves the properties of the SEI and the safety of the battery, while preventing the creation of shorts-circuits usually originated from Li dendrites.
The motivation for MONPs addition was initially the idea that MONPs attract ions, thus could increase the effective concentration of the electrolyte. Deep investigation revealed an unexpected phenomenon, in which many battery parameters are affected by the additives, from the different resistance values of the battery, through SEI morphology and chemical composition, to the life span of the battery.

It is hard to overstate the importance of batteries in the modern age.
The importance of batteries is widely known as it meets almost any aspect of our day-to-day life. Batteries meets us at our cellphone, our computer and today more and more at our public and private vehicle.
Increasing the energy density by 50% while maintaining the life span of currently used batteries, has the potential to revolutionize our charging habits and the efficiency of green energy (solar and wind) use and storage.

Laboratory scale batch was developed. So far, we have demonstrated a positive effect to all subjected Li-chemistries batteries. 
Our experimental data strongly support the hypothesis that the improvement mechanism relays on more than one path.

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