Novel Methods for Coating Li4Ti5O12 Particles: Boosting Performances of Li-Ion Batteries

Abstract

One of the promising approaches for limiting climate changes is to use alternatives and greener sources of energy (wind, solar, etc.). However, the production of electricity from these sources is fluctuant and needs a solution for storage thus, the advent of energy storage for wind power, solar plant, etc., requires a new generation of batteries in order to optimize the use of these alternative sources of energy. To do so, the development of a battery with a high rate of charging and discharging, a longer cycle life and safe is imperative.We devoted our efforts to develop LFP-LTO batteries; this presentation will highlight our avenues to limit the gas evolution in a battery; novel methods for coating will be presented, the use of polymers to protect the surface of the active inorganic particles in order to limit the degradation of the electrolyte. Two methods to graft polymers on particles (LTO) were applied with success for preventing degradation of LFP-LTO cells. Because battery environments are aggressive (HF formation, pH = 2), we developed a new robust method for grafting hydrophobic polymers on active particles (LTO) by Williamson Ether Synthesis, which is compatible with the manufacturing of electrodes, and prevented significant cell degradation over extensive cycling. They were able to limit the degradation of the battery by increasing the capacity retention and stabilizing the resistance of the electrode with the accelerated aging. The other method (grafting from) allows the formation of shells by a myriad of polymers, therefore particles become compatible with any kind of polymeric binders. Electrochemical performances will be shown with different compositions.Moreover, we reported on the development of an economical, eco-friendly, and scalable method of making a homogenous 3D network coating of N-doped carbons on LTO particles. Our method makes it possible, for the first time, to fill the pores of secondary particles with carbons; we revealed that it is possible to cover each primary nanoparticle. This unique approach permited the creation of lithium-ion batteries with outstanding performances during ultra-fast charging (4 C and 10 C), and demonstrated an excellent ability to inhibit the degradation of cells over time. This new method allowed removal of conductive carbons in anode fabrication, therefore active materials compose up to 96 wt% in electrodes.These methods are valuable for large production because it is inexpensive and easy to scale up.