Diffusion-induced stress optimization by boosted surface Li-concentration for single-crystal Ni-rich layered cathodes
Volume 61, Issue , Page 40–53
| Qi Wang, Lai Chen, Zhiming Xiao, Xinming Fan, Shuailing Ma, Lei Ming, Akhil Tayal, Bao Zhang, Feng Wu, Xing Ou
Abstract
Nickel-rich layered LiNixCoyMn1-x-yO2 (NCM, x ≥ 0.83) is considered as a promising cathode material for lithium-ion batteries (LIBs), owing to its satisfying specific energy. However, the undesired phase transformation from layered into rock-salt at the NCM surface will easily induce Li concentration gradient during cycling, which hinders the Li-ions diffusion and leads to the gradual accumulation of inner stress with the appearance of microcracks. Herein, we propose a surficial engineering strategy to promote the Li-ions transmission for single-crystalline LiNi0.83Co0.11Mn0.06O2 (SCNCM) via Li1.3In0.3Ti1.7(PO4)3 (LITP) modification. It is noted that, as the fast Li-ion conductor, LITP can accelerate the Li-ions diffusion and alleviate the electrode–electrolyte side reaction simultaneously. More importantly, LITP can serve as the Li-ions regulator, ensuring the homogeneous distribution of Li-ions and minimizing the concentration difference at SCNCM surface. It can relieve the stress induced by the inconsistent Li-ions dispersion, which effectively decreases the degree of structural disordering and lattice mismatch at surface, eventually maintaining the high structure integrity during long-term cycling. As anticipated, even under the harsh testing conditions, the LITP modified SCNCM still can achieve a satisfied reversible capacity of 196.4 mAh g−1 under potential range of 2.75–4.6 V after 200 cycles at 25 °C in coin-type half-cells. Furthermore, it provides an extraordinary capacity retention of 88% in 2.75–4.3 V after 400 cycles at high temperature of 45 °C in pouch-type full-battery.
A surficial engineering strategy for single-crystalline LiNi0.83Co0.11Mn0.06O2 (SCNCM) via Li1.3In0.3Ti1.7(PO4)3 (LITP) modification is proposed to promote the Li-ions distribution. Notably, the fast Li-ion conductor LITP can not only accelerate the Li-ions diffusion and alleviate the electrode–electrolyte side reaction simultaneously, but also serve as the Li-ions regulator to ensure the homogeneous distribution of Li-ions and minimizing the concentration difference at SCNCM surface. It provides the instructive guide for the modification of single-crystalline micron-sized particles for commercialization development of advanced NCM cathode at harsh testing condition.See full text for more information.
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DOI: 10.1016/j.mattod.2022.10.021
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