Cross‐Talk‐Suppressing Electrolyte Additive Enabling High Voltage Performance of Ni‐Rich Layered Oxides in Li‐Ion Batteries
Hieu Quang Pham, Minh Tri Nguyen, Mohamed Tarik, Mario El Kazzi, Sigita Trabesinger
Abstract
Abstract Control of electrode‐electrolyte interfacial reactivity at high‐voltage is a key to successfully obtain high‐energy‐density lithium‐ion batteries. In this study, 2‐aminoethyldiphenyl borate (AEDB) is investigated as a multifunctional electrolyte additive in stabilizing surface and bulk of both Ni‐rich LiNi 0.85 Co 0.1 Mn 0.05 O 2 (NCM851005) and graphite electrodes in a cell operated with elevated upper cutoff voltage of 4.4 V vs. Li + /Li. The presence of AEDB in a full‐cell inhibits structural degradation of both cathode and anode materials, suppressing crack formation, and reduces metal dissolution at the cathode and metal deposition at the anode. As a consequence, the interfacial resistance is significantly reduced. Moreover, this is a case where “the whole is greater than the sum of the parts”: the effect of AEDB in half‐cells is rather modest, whereas in full‐cells its addition results in tremendous performance improvement. The graphite‖NCM851005 full‐cell in the presence of AEDB has a capacity retention of 88 % after 100 cycles, even when the upper cutoff voltage is set to 4.35 V, corresponding to 4.4 V vs Li + /Li, whereas with standard electrolyte under the same conditions it is only 21 %. The study shows a simple and easy approach to using Ni‐rich cathodes in an extended voltage window and demonstrates the importance of full‐cell testing for electrolyte additive selection.