Construction of Low‐Impedance and High‐Passivated Interphase for Nickel‐Rich Cathode by Low‐Cost Boron‐Containing Electrolyte Additive

Abstract

The nickel-rich cathode LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) possesses the advantages of high reversible specific capacity and low cost, thus regarded as a promising cathode material for lithiumion batteries (LIBs). However, the capacity of the NCM811 decays rapidly at high voltage due to the extremely unstable electrode/electrolyte interphase. The discharge capability at low temperature is also impaired because of the increasing interfacial impedance. Herein, a low-cost film-forming electrolyte additive with multi-function, phenylboronic acid (PBA), was employed to modify the interphasial properties of the NCM811 cathode. Theoretical calculation and experimental results showed that PBA constructed a highly conductive and steady cathode electrolyte interphase (CEI) film through preferential oxidation decomposition, which greatly improved the interfacial properties of the NCM811 cathode at room (25 °C) and low temperature (À 10 °C). Specifically, the capacity retention of NCM811/Li cell was increased from 68 % to 87 % after 200 cycles with PBA additive. Moreover, the NCM811/Li cell with PBA additive delivered higher discharge capacity under À 10 °C at 0.5 C (173.7 mAh g À 1 vs. 111.1 mAh g À 1 ). Based on the improvement of NCM811 interphasial properties by additive PBA, the capacity retention of NCM811/graphite full-cell was enhanced from 49 % to 65 % after 200 cycles.

Stabilization of NCM811 cathode interface through macromolecular compound protective film formed by 2,5-bis(2,2,2-trifluoroethoxy)-benzoic acid additive in lithium metal batteries

“…The cracks intensify parasitic reactions between the NCM811 and electrolyte, leading to continuous depletion of active substances and rapid capacity loss. 29 Additionally, the cycled Li/NCM811 battery lacking 2,5BTBA exhibits characteristic mossy dendrites on the lithium metal anode, evident in Fig. 1e and f .…”

Multifunctional Electrolyte Additive for High-Nickel LiNi0.8Co0.1Mn0.1O2 Cathodes of Lithium-Metal Batteries

“…The presence of a N-containing compound in the PFPN electrolyte proves that it can form a CEI with organic matter containing nitrogen. In N 1s spectra, -PN-P moieties were detected at the peak of 399.0 eV; however, the signal peak of nitrogen compounds was undetectable in the blank electrolyte. − The rich P–O species (135.1 eV) observed in the P 2p spectrum (Figure d) could be partly attributed to the decomposition or polymerization of PFPN as well, and PN- moieties were detected at the peak of 134.2 eV, proving that PFPN could inhibit the dissociation of salt. In F 1s spectra (Figure c), the intensities of LiF are (684.8 eV) reduced, probably owing to the slow decomposition of LiPF 6 salt on the NCM811 cathode surface.…”

Improving the Electrochemical Performance of NCM811 ∥ SiO/Gr Pouch Cells by Interface Modification with Anhydride Electrolyte Additives

“…9−13 Particularly, the positively charged NCM811 has strong electrochemical activity especially at high voltage and varied temperature, resulting in a very unstable electrode/ electrolyte interface and electrolyte decomposition. 14,15 In order to solve the aforementioned issues, electrolyte additives have been employed and demonstrated an effective strategy to improve battery performance. For instance, anhydrides are believed to be beneficial to the batteries that are cycled at high temperature, 16,17 whereas benzenecontaining species are good for low-temperature capacity retention.…”

“…Rechargeable lithium-ion batteries (LIBs) as a clean energy storage technology has been successfully employed in a variety of applications, including electric vehicles, cell phones, and portable electronics. − Recently, further performance improvements have been achieved through the development of Ni-rich cathodes, such as LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811). This cathode material is considered to be the most likely choice for the next generation of LIBs due to its high specific discharge capacity and cost-effectiveness when compared to other materials. , It has been demonstrated that raising the content of nickel in NCM typically increases the specific discharge capacity yet suffers from obvious capacity attenuation and performance degradation during cycling mainly due to the phase transformation and side reactions under high voltage. − Particularly, the positively charged NCM811 has strong electrochemical activity especially at high voltage and varied temperature, resulting in a very unstable electrode/electrolyte interface and electrolyte decomposition. , …”