Cross‐Talk‐Suppressing Electrolyte Additive Enabling High Voltage Performance of Ni‐Rich Layered Oxides in Li‐Ion Batteries

Abstract

Control of electrode-electrolyte interfacial reactivity at highvoltage 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 Li-Ni 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 graphitejjNCM851005 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.

Advances in studying interfacial reactions in rechargeable batteries by photoelectron spectroscopy

“…Such compounds added to the electrolyte, typically in concentrations of <10 %, are often designed to improve interfacial chemistry. [109][110][111][112][113] The role of tris(trimethylsilyl) phosphite (TMSPi) as an electrolyte additive to improve the electrochemical performance of NMC811/Si-Graphite cells was investigated by synchrotron-based XPS depth profiling. 114 The morphological and compositional differences of the CEI and SEI were probed for the cathode and anode, respectively.…”

“…Such compounds added to the electrolyte, typically in concentrations of <10%, are often designed to improve interfacial chemistry. 109–113…”

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

“…Based on this mechanism, the MTE-TMS additive causes an improvement in cycling performance and coulombic efficiency. Pham et al [ 11 ] reported 2-aminoethyl diphenyl borate (AEDB) as a multifunctional electrolyte additive for improving the electrochemical properties of the battery. AEDB possesses a special chemical structure for relieving surface degradation reactions.…”

“…Furthermore, the cathode materials serve as the provider of lithium-ions, which greatly determines the capacity of LIBs. Nowadays, a great deal of research work has been done to develop cathode materials with superior specific capacities at high operating voltage [ 11 ].…”

Uracil-based additives for enabling robust interphases of high-voltage Li-ion batteries at elevated temperature by substituent effects

“…1,2 So far, one of the main ways to achieve the ultrahigh energy density of LIBs has been to increase the operating voltages (44.3 V) in the state-of-art batteries. [3][4][5] However, the actual application of high-voltage LIBs still faces some formidable obstacles, i.e., the adverse reactions at the interfaces between electrodes and liquid electrolytes, in particular for the Ni-rich LIBs at extremely high temperatures. [6][7][8] However, the solid electrolyte interphase (SEI) on the surfaces of electrodes, which originally play an important role in interfacial protective layers, is continuously damaged and regrows at high potentials during the chargedischarge cycling.…”