Direct In situ Observation of Li2O Evolution on Li-Rich High-Capacity Cathode Material, Li[NixLi(1–2x)/3Mn(2–x)/3]O2 (0 ≤ x ≤0.5)

Hy, Sunny; Felix, Felix; Rick, John; Su, Wei‐Nien; Hwang, Bing‐Joe

doi:10.1021/ja410137s

Cited by 408 publications

(322 citation statements)

References 50 publications

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“…The formation of thick SEI layer at the surface of the bare LNCM leads to its poor rate capability and severe capacity drop during cycling. Furthermore, structural collapse of active materials is often accelerated by the surface side reactions with electrolyte 6, 13, 16, 32. As a result, the bare LNCM sample shows severe phase distortion after the cycling at 55 °C (Figure S7, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

High‐Performance Heterostructured Cathodes for Lithium‐Ion Batteries with a Ni‐Rich Layered Oxide Core and a Li‐Rich Layered Oxide Shell

et al. 2016

Advanced Science

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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 LiNi0.7Co0.15Mn0.15O2 core and a Li‐rich Li1.2− xNi0.2Mn0.6O2 shell, incorporating the advantageous features of the structural stability of the core and chemical stability of the shell. With a unique chemical treatment for the activation of the Li2MnO3 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. As a result, 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).

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Section: Resultsmentioning

confidence: 99%

High‐Performance Heterostructured Cathodes for Lithium‐Ion Batteries with a Ni‐Rich Layered Oxide Core and a Li‐Rich Layered Oxide Shell

et al. 2016

Advanced Science

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“…In Figures 4c-4d, the LNMO demonstrates large discharge voltage slippage, which indicates the rapid growth of cathode electrolyte interphase (CEI) on the surface of LNMO. [4][5][6] This undesired CEI traps or slows down the lithium diffusion, thus causing serious capacity and voltage degradation in LNMO. In the case of LP600, the CEI is mitigated by the Li 3 PO 4 coating layer by reducing direct contact between the electrode and electrolyte.…”

Section: Figure 1 Sem Images: (A)-(h)mentioning

confidence: 99%

Communication—Enhancing the Electrochemical Performance of Lithium-Excess Layered Oxide Li_1.13Ni_0.3Mn_0.57O₂ via a Facile Nanoscale Surface Modification

Liu

Huang

Qian

et al. 2016

J. Electrochem. Soc.

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In this work, a facile surface modification with nanoscale equilibrium Li 3 PO 4 -based surface amorphous films (SAFs) has been applied to Lithium-excess layered oxide Li 1.13 Ni 0.3 Mn 0.57 O 2 , which significantly improves the first cycle coulombic efficiency, rate capability, and cycling stability. The nanoscale surface modification can be easily achieved by ballmilling and isothermal annealing. The optimized surface modified Li 1.13 Ni 0.3 Mn 0.57 O 2 is capable of maintaining a high capacity of 201 mAh g −1 after 60 cycles at 55 • C testing with a rate of 1 C. This work provides a facile and scalable surface modification method to improve electrochemical performance of cathode materials for lithium ion batteries. The Lithium-excess layered oxides benefit from an extraordinary high reversible capacity (>280 mAh g −1 ) and is one of the most promising cathode materials for plug-in electric vehicle application. [1][2][3] However, this high-energy-density material suffers from large irreversible capacity in its first electrochemical cycle when it is charged to high voltages, namely more than 4.6 V. In addition, its rate capability is yet unsatisfactory for high power application. Moreover, the gradual voltage and capacity degradation upon electrochemical cycling, especially at elevated temperature when side reactions related to the interactions with the electrolyte occur more prevalently, represent the most serious technical challenge for this material. 4,5 In the past few years, significant amount of surface modification works have been carried out to protect the surfaces of the Li-excess. Most of the reported surface modifications are performed under solution-based reactions.6-8 For example, Bian et al. used LiOH and NH 4 H 2 PO 4 to coat Lithium-excess with Li 3 PO 4 .7 However, the solution based surface modification adds an additional layer of complexity for preparation of Lithium-excess, which will definitely raise the cost of production. Although Konishi coated high voltage spinel LiNi 0.5 Mn 1.5 O 4 with uniform Li 3 PO 4 via pulsed laser deposition (PLD), this technique requires special equipment, which is difficult to realize for large scale production. 9In this work, we modify the surface of Lithium-excess layered oxide Li 1.13 Ni 0.3 Mn 0.57 O 2 via simple mixing and calcination to form Li 3 PO 4 -enriched and nanometer-thick surface amorphous films (SAFs). 10 Our results indicate that the optimized material shows remarkably improved performance. ExperimentalThe synthesis of the Li-excess is described in our previous publications. 3,6 The procedure for preparing Li 3 PO 4 surface modified Li 1.13 Ni 0.3 Mn 0.57 O 2 (LPLNMO) was adapted from work by Huang et al.10 0.06 g Li 3 PO 4 (Alfa Aesar, 99.99%) and 3 g Li 1.13 Ni 0.3 Mn 0.57 O 2 were mixed using a planetary ball mill (PM 100, Retsch). The powder was calcinated at 500• C (LP500), 600• C (LP600), and 700• C (LP700), respectively, for 5 h in air. Electrochemical test, XRD, SEM and HRTEM characterization are described with details in our previous...

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“…14,15 It has been clarified that the charge compensation mechanism of the electrochemical oxidation reaction around 4.5 V at the first cycle is not related to further oxidation of Co 4+ , Ni 4+ or Mn 4+ , [15][16][17][18][19] but quite possibly to the electron loss of lattice oxygen. 11,20,21 This could cause the formation of superoxide 22,23 or oxygen loss, 11 leading to the formation of oxygen vacancy, 24,25 and/or lattice densification, 26,27 leading to the unstable lattice. In However, its electrochemical behavior is quite different from LiCrO 2 and Li 2 MnO 3 components.…”

Section: Introductionmentioning

confidence: 99%

Probing Reversible Multielectron Transfer and Structure Evolution of Li_1.2Cr_0.4Mn_0.4O₂ Cathode Material for Li-Ion Batteries in a Voltage Range of 1.0–4.8 V

Lyu

Zhao

et al. 2015

Chem. Mater.

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Li 1.2 Cr 0.4 Mn 0.4 O 2 (0.4LiCrO 2 ⋅0.4Li 2 MnO 3 ) is an interesting intercalation-type cathode material with high theoretical capacity of 387 mAh g -1 based on multiple-electron transfer of Cr 3+ /Cr 6+ . In this work, it has been demonstrated that the reversible Cr 3+ /Cr 6+ redox reaction can only be realized in a wide voltage range between 1.0 V and 4.8 V. This is mainly due to large polarization during the discharge. The reversible migration of the Cr ions between octahedral and tetrahedral sites leads to large extent of cation mixing between lithium and transition metal layers, which doesn't affect the lithium storage capacity and stabilize the structure. In addition, a distorted spinel phase (Li 3 M 2 O 4 ) is identified in the deeply discharged sample (1.0 V, Li 1.5 Cr 0.4 Mn 0.4 O 2 ). Above results can explain the high reversible capacity and high structural stability achieved on Li 1.2 Cr 0.4 Mn 0.4 O 2 . These new findings will provide further in depth understanding on multi-electron transferand local structure stabilization mechanisms in intercalation chemistry, which are essential for understanding and developing high capacity intercalation-type cathode for next generation high energy density Li-ion batteries.

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Direct In situ Observation of Li₂O Evolution on Li-Rich High-Capacity Cathode Material, Li[Ni_xLi_(1–2x)/3Mn_(2–x)/3]O₂ (0 ≤ x ≤0.5)

Cited by 408 publications

References 50 publications

High‐Performance Heterostructured Cathodes for Lithium‐Ion Batteries with a Ni‐Rich Layered Oxide Core and a Li‐Rich Layered Oxide Shell

High‐Performance Heterostructured Cathodes for Lithium‐Ion Batteries with a Ni‐Rich Layered Oxide Core and a Li‐Rich Layered Oxide Shell

Communication—Enhancing the Electrochemical Performance of Lithium-Excess Layered Oxide Li_1.13Ni_0.3Mn_0.57O₂ via a Facile Nanoscale Surface Modification

Probing Reversible Multielectron Transfer and Structure Evolution of Li_1.2Cr_0.4Mn_0.4O₂ Cathode Material for Li-Ion Batteries in a Voltage Range of 1.0–4.8 V

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Direct In situ Observation of Li2O Evolution on Li-Rich High-Capacity Cathode Material, Li[NixLi(1–2x)/3Mn(2–x)/3]O2 (0 ≤ x ≤0.5)

Cited by 408 publications

References 50 publications

High‐Performance Heterostructured Cathodes for Lithium‐Ion Batteries with a Ni‐Rich Layered Oxide Core and a Li‐Rich Layered Oxide Shell

High‐Performance Heterostructured Cathodes for Lithium‐Ion Batteries with a Ni‐Rich Layered Oxide Core and a Li‐Rich Layered Oxide Shell

Communication—Enhancing the Electrochemical Performance of Lithium-Excess Layered Oxide Li1.13Ni0.3Mn0.57O2 via a Facile Nanoscale Surface Modification

Probing Reversible Multielectron Transfer and Structure Evolution of Li1.2Cr0.4Mn0.4O2 Cathode Material for Li-Ion Batteries in a Voltage Range of 1.0–4.8 V

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Direct In situ Observation of Li₂O Evolution on Li-Rich High-Capacity Cathode Material, Li[Ni_xLi_(1–2x)/3Mn_(2–x)/3]O₂ (0 ≤ x ≤0.5)

Communication—Enhancing the Electrochemical Performance of Lithium-Excess Layered Oxide Li_1.13Ni_0.3Mn_0.57O₂ via a Facile Nanoscale Surface Modification

Probing Reversible Multielectron Transfer and Structure Evolution of Li_1.2Cr_0.4Mn_0.4O₂ Cathode Material for Li-Ion Batteries in a Voltage Range of 1.0–4.8 V