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Title: A facile cathode design combining Ni-rich layered oxides with Li-rich layered oxides for lithium-ion batteries

Abstract

A facile synthesis method was developed to prepare xLi 2MnO 3·(1-x)LiNi 0.7Co 0.15Mn 0.15O 2 (x = 0, 0.03, 0.07, 0.10, 0.20, and 0.30 as molar ratio) cathode materials, combining the advantages of high specific capacity from Ni-rich layered phase and surface chemical stability from Li-rich layered phase. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM) and electrochemical charge/discharge performance confirm the formation of a Li-rich layered phase with C2/m symmetry. Most importantly, high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) reveals a spatial relationship that Li-rich nano-domain islands are integrated into a conventional Ni-rich layered matrix (R$$\bar{3}$$m). This is the first time that Li-rich phase has been directly observed inside a particle at the nano-scale, when the overall composition of layered compounds (Li 1+δNi xMn yM 1-x-y-δO 2, M refers to transition metal elements) is Ni-rich (x > 0.5) rather than Mn-rich (y > 0.5). Remarkably, xLi 2MnO 3·(1-x)LiNi 0.7Co 0.15Mn 0.15O 2 cathode with optimized x value shows superior electrochemical performance at C/3, i.e., 170 mA h g -1 with 90.3 % of capacity retention after 400 cycles at 25 °C and 164 mA h g -1 with 81.3 % capacity retention after 200 cycles at 55 °C.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340858
Report Number(s):
PNNL-SA-115253
Journal ID: ISSN 0378-7753; 48379; KP1704020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Power Sources; Journal Volume: 325; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; Environmental Molecular Sciences Laboratory

Citation Formats

Song, Bohang, Li, Wangda, Yan, Pengfei, Oh, Seung-Min, Wang, Chong-Min, and Manthiram, Arumugam. A facile cathode design combining Ni-rich layered oxides with Li-rich layered oxides for lithium-ion batteries. United States: N. p., 2016. Web. doi:10.1016/j.jpowsour.2016.06.056.
Song, Bohang, Li, Wangda, Yan, Pengfei, Oh, Seung-Min, Wang, Chong-Min, & Manthiram, Arumugam. A facile cathode design combining Ni-rich layered oxides with Li-rich layered oxides for lithium-ion batteries. United States. doi:10.1016/j.jpowsour.2016.06.056.
Song, Bohang, Li, Wangda, Yan, Pengfei, Oh, Seung-Min, Wang, Chong-Min, and Manthiram, Arumugam. Thu . "A facile cathode design combining Ni-rich layered oxides with Li-rich layered oxides for lithium-ion batteries". United States. doi:10.1016/j.jpowsour.2016.06.056.
@article{osti_1340858,
title = {A facile cathode design combining Ni-rich layered oxides with Li-rich layered oxides for lithium-ion batteries},
author = {Song, Bohang and Li, Wangda and Yan, Pengfei and Oh, Seung-Min and Wang, Chong-Min and Manthiram, Arumugam},
abstractNote = {A facile synthesis method was developed to prepare xLi2MnO3·(1-x)LiNi0.7Co0.15Mn0.15O2 (x = 0, 0.03, 0.07, 0.10, 0.20, and 0.30 as molar ratio) cathode materials, combining the advantages of high specific capacity from Ni-rich layered phase and surface chemical stability from Li-rich layered phase. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM) and electrochemical charge/discharge performance confirm the formation of a Li-rich layered phase with C2/m symmetry. Most importantly, high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) reveals a spatial relationship that Li-rich nano-domain islands are integrated into a conventional Ni-rich layered matrix (R$\bar{3}$m). This is the first time that Li-rich phase has been directly observed inside a particle at the nano-scale, when the overall composition of layered compounds (Li1+δNixMnyM1-x-y-δO2, M refers to transition metal elements) is Ni-rich (x > 0.5) rather than Mn-rich (y > 0.5). Remarkably, xLi2MnO3·(1-x)LiNi0.7Co0.15Mn0.15O2 cathode with optimized x value shows superior electrochemical performance at C/3, i.e., 170 mA h g-1 with 90.3 % of capacity retention after 400 cycles at 25 °C and 164 mA h g-1 with 81.3 % capacity retention after 200 cycles at 55 °C.},
doi = {10.1016/j.jpowsour.2016.06.056},
journal = {Journal of Power Sources},
number = C,
volume = 325,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2016},
month = {Thu Sep 01 00:00:00 EDT 2016}
}
  • In this work, to address the growing demand for energy density, the Ni-rich layered [Ni 0.90Co 0.05Mn 0.05]O 2 cathode has been synthesized and its electrochemical performance in lithium-ion cells has been benchmarked against a lower-Ni content Li[Ni 0.6Co 0.2Mn 0.2]O 2 cathode. Li[Ni 0.90Co 0.05Mn 0.05]O 2 delivers a high discharge capacity of 227 mA h g -1 compared to a capacity of 189 mA h g -1 for Li[Ni 0.6Co 0.2Mn 0.2]O 2 when cycled up to a lower cutoff voltage of 4.3 V, making it an appealing candidate for electric vehicles. With an increase in the chargemore » cutoff voltage to 4.5 V, Li[Ni 0.90Co 0.05Mn 0.05]O 2 displays a capacity of 238 mA h g -1 compared to a capacity of 208 mA h g -1 for Li[Ni 0.6Co 0.2Mn 0.2]O 2. Although Li[Ni 0.90Co 0.05Mn 0.05]O 2 suffers during cycling from the usual rapid capacity fade in a manner similar to that of LiNiO 2, 87 and 81% of the initial capacity could still be retained after 100 cycles even after cycling to higher cutoff voltages of 4.3 and 4.5 V, respectively. A comparison of Li[Ni 0.90Co 0.05Mn 0.05]O 2 and Li[Ni 0.6Co 0.2Mn 0.2]O 2 reveals that the capacity fade of Li[Ni 0.90Co 0.05Mn 0.05]O 2 originates largely from the anisotropic volume change and subsequent microcrack propagation in the bulk and NiO-like rock salt impurity phase formation on the particle surface, which are exacerbated at 4.5 V. Lastly, future work with appropriate doping and surface modification could improve further the performance of Li[Ni 0.90Co 0.05Mn 0.05]O 2.« less
  • The Ni-rich layered oxides with a Ni content of >0.5 are drawing much attention recently to increase the energy density of lithium-ion batteries. However, the Ni-rich layered oxides suffer from aggressive reaction of the cathode surface with the organic electrolyte at the higher operating voltages, resulting in consequent impedance rise and capacity fade. To overcome this difficulty, we present here a heterostructure composed of a Ni-rich LiNi 0.7Co 0.15Mn 0.15O 2 core and a Li-rich Li 1.2-xNi 0.2Mn 0.6O 2 shell, incorporating the advantageous features of the structural stability of the core and chemical stability of the shell. With amore » unique chemical treatment for the activation of the Li 2MnO 3 phase of the shell, a high capacity is realized with the Li-rich shell material. Aberration-corrected scanning transmission electron microscopy (STEM) provides direct evidence for the formation of surface Li-rich shell layer. Finally, the heterostructure exhibits a high capacity retention of 98% and a discharge- voltage retention of 97% during 100 cycles with a discharge capacity of 190 mA h g -1 (at 2.0–4.5 V under C/3 rate, 1C = 200 mA g -1).« less
  • Highlights: • A coralline-like Li{sub 1.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode was synthesized by hydrothermal method. • Initial discharge capacity of 250.2 mAh g{sup −1} for the cathode was obtained at 0.1 C. • A high reversible specific capacity of 210.2 mAh g{sup −1} after 100 cycles was acquired. • The high capacity retention of 84.5% was obtained even after 200 cycles at 10 C. - Abstract: A coralline-like lithium-rich layered cathode material with homogeneous composition of Li{sub 1.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} has been successfully synthesized via a facile ethanolamine (EA)-mediated hydrothermal method route, with subsequent calcination at 850more » °C. An initial specific discharge capacity of 250.2 mAh g{sup −1} and a reversible specific capacity of 210.2 mAh g{sup −1} after 100 cycles at a constant density of 25 mA g{sup −1} (1 C = 250 mA g{sup −1}) are acquired. Even at 10 C, it still delivers a discharge capacity of approximately 100 mA h g{sup −1}, thereby indicating its excellent high power performance. The sample also shows enhanced cycling performance with 88.5%, 79.9% and 90.5% of capacity retention after 100 cycles at 0.5, 5 and 10 C rates, respectively. Besides, 84.5% of initial capacity is retained even after 200 cycles at 10 C. Consequently, the fascinating electrochemical performance may facilitate the coralline-like LMNCO composite to be a promising alternative cathode for LIBs with a high application potential.« less