Role of Electrolyte in Overcoming the Challenges of LiNiO₂ Cathode in Lithium Batteries

Abstract

LiNiO 2 (LNO) is a high-capacity and model cathode first discovered in the 1980s that fell out of favor due to its intrinsic instabilities. However, research activities toward LNO are once again on the rise as the push for higher-energy-density cells marches on. We demonstrate here that with appropriate modern electrolytes, major performance improvements can be achieved with LNO with no additional modifications. Cells with a localized high concentration electrolyte (LHCE) deliver 92% capacity retention after 200 cycles compared with 56% capacity retention in a baseline carbonate electrolyte, maintain 94% capacity after high-voltage storage compared with 77% capacity, and display a higher onset temperature of thermal runaway of 244 °C compared with 188 °C. These improvements are attributed to the LHCE's high oxidative stability and its formation of fluorine-rich interphases. Although further characterization of this new class of electrolyte is necessary, this work demonstrates that modern electrolytes can be dropin enablers of high-capacity, long-cycle-life cells.

Gas Generation in Lithium Cells with High-Nickel Cathodes and Localized High-Concentration Electrolytes

“…Coatings and dopants are classic modifications, which can passivate the surface or bulk of the cathode itself. , Electrolyte modifications also have a strong effect on the reaction between the electrolyte and the cathode, where the organic solvent is especially relevant to the electrolyte’s thermal and gas responses. , Some classes of solvent and electrolyte are inherently nonflammable, although the reduced flammability generally comes at the expense of other metrics, such as cycle life or operating temperature . Meanwhile, a class of electrolyte has been recently developed, which appears to provide benefits across most metrics: the localized high-concentration electrolyte (LHCE). − In a typical high-concentration electrolyte (HCE), solvent molecules are fully or nearly fully coordinated to salt. The high degree of coordination lowers the free energy of the solvent, effectively widening its voltage stability window and reducing its reactivity.…”

A uniform and high-voltage stable LiTMPO4 coating layer enabled high performance LiNi0.8Co0.15Mn0.05O2 towards boosting lithium storage

“…3d). 33 The bonding energies of Ni 2p indexed at 873.1 eV and 855.6 eV correspond to Ni 2p 1/2 and Ni 2p 3/2 (Fig. 3e).…”

Degradation Pathways of Cobalt-free LiNiO2 Cathode in Lithium Batteries

“…1c) in the baseline electrolyte LP57 (1 M LiPF6 in EC/EMC (w/w, 3/7) with 2 wt.% VC) is also achieved when bench-marked to literature reports. 13,16,23,24 However, its capacity drops more than 20% after 100 cycles and only retains 54% of the initial capacity at a C/2-1C rate after 200 cycles. In sharp contrast, with the 20F1P electrolyte, the cycling stability experiences a dramatic improvement.…”

“…High quality LNO spherical secondary particles were synthesized in-house, and detailed experimental procedure is available reported in our previous study. 16 Briefly, Ni(OH)2 precursor was synthesized via hydroxide coprecipitation in a 10 L continuously stirred tank reactor, with the a starting solution of 2 M NiSO4. After the coprecipitation reaction, the precursor was filtered, washed, and stored in an oven at 110 ℃ for The cracked LNO particles were used for electrode fabrication with the same procedure.…”

“…[6][7][8] With the recently revived interest in LNO cathode, various approaches to address its stability issues have been proposed, including surface coating, 9,10 elemental doping, [11][12][13] particle morphology manipulation, 14 single crystal, 15 and electrolyte modification. 16 However, significant improvements are yet to be made before practical application of LNO in LIBs can be achieved.…”