Surface Stabilization of Cobalt-Free LiNiO₂ with Niobium for Lithium-Ion Batteries

Abstract

Lithium nickel oxide (LiNiO2) is a promising next-generation cathode material for lithium-ion batteries (LIBs), offering exceptionally high specific capacity and reduced material cost. However, the poor structural, surface, and electrochemical stabilities of LiNiO2 result in rapid loss of capacity during prolonged cycling, making it unsuitable for application in commercial LIBs. Herein, we demonstrate that incorporation of a small amount of niobium effectively suppresses the structural and surface degradation of LiNiO2. The niobium-treated LiNiO2 retains 82% of its initial capacity after 500 cycles in full cells with a graphite anode compared to 73% for untreated LiNiO2. We utilize a facile method for incorporating niobium, which yields Li x NbO y phase formation as a surface coating on the primary particles. Through a combination of X-ray diffraction, electron microscopy, and electrochemical analyses, we show that the resulting niobium coating reduces active material loss over long-term cycling and enhances lithium-ion diffusion kinetics. The enhanced structural integrity and electrochemical performance of the niobium-treated LiNiO2 are correlated to a reduction in the formation of nanopore defects during cycling compared to the untreated LiNiO2.

The role of niobium in layered oxide cathodes for conventional lithium-ion and solid-state batteries

“…Ober et al also reported a similar finding, where the formation of intergranular Li x NbO y phases in LNO impeded the growth of its primary particles. 153 Hence, as previously emphasized, temperature conditions significantly influence niobium modification of LTMOs, and the possibility of an additional coating on the particle surface, including the primary particles themselves, should be considered.…”

“…112,129,130,136,152 On the other hand, when the primary particles are compared, niobium appears to cause a significant reduction in their sizes. 59,119,120,128,153 Park et al showed an interesting study in this regard using different high-valence elements (Al 3+ , Nb 5+ , Ta 5+ , and Mo 6+ ) to dope LNO. 115 The samples were prepared by mixing Ni(OH) 2 , LiOH, and dopant precursor, with further calcination within the temperature range of 650 to 800 °C.…”

Cobalt‐Free LiNiO2 with a Selenium Coating as a High‐Energy Layered Cathode Material for Lithium‐Ion Batteries

“…[11][12][13] Among these cathode materials, Co-free layered lithium nickel oxide (LiNiO 2 ) is undoubtedly the most distinctive, with a maximum theoretical specific capacity of 270 mAh g À1 at a higher-voltage plateau (3.8 V vs Li/Li þ ). [14][15][16][17][18][19][20] However, LiNiO 2 cathodes suffer from deterioration of the material surface and physical structure during cycling due to several reasons. During the synthesis of LiNiO 2 , a large amount of Ni 2þ cannot be oxidized to Ni 3þ .…”

“…Because the ionic radius of Ni 2þ (0.068 nm) is similar to that of Li þ (0.076 nm), Ni 2þ can easily occupy the original position of Li þ , leading to a phase transition and Li þ /Ni 2þ disorder. [15,19] Furthermore, Ni 4þ generated during the charging process reacts with the electrolyte, resulting in the loss of the oxygen lattice and structural collapse of the cathode surface. [18,20] Moreover, the tension induced by repetitive volume contraction and expansion during cycling may result in microcracks on the surface of the cathode materials.…”

Cascading degradations artificially improving the lifetime of Li-ion full cells using DMC-based highly concentrated electrolyte

“…Facing up this challenge, recent years have seen a surge of efforts dedicated to the design and the stabilization of Ni-rich NMC materials using diverse approaches as the doping of active materials [19][20][21] , the design of surface coatings [22][23][24] or the use of additives for high voltage [25][26][27] . One strategy recently proposed to tackle instabilities at high potential is the use of so-called highly concentrated electrolytes (HCE) 28 .…”