Strain Engineering of Ni‐Rich Cathode Enables Exceptional Cyclability in Pouch‐Type Full Cells

Zhu, Huasheng; Wang, Zhihong; Chen, Ling; Hu, Yanjie; Jiang, Hao; Li, Chunzhong

doi:10.1002/adma.202209357

Cited by 47 publications

(33 citation statements)

References 45 publications

(37 reference statements)

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“…The corresponding unit cell shows a 3.27% volume shrinkage in the r-NCM811, whereas it shows 4.84% in the c-NCM811 during the whole charge process (Figure D). These results manifest that the r-NCM811 possesses obvious microstrain relaxation advantages with a partially isotropic volume change because of their high aspect ratio primary particles, greatly alleviating the cracking of the second particles. ,, This deduction has been confirmed by their cross-sectional SEM images when charged to 4.3 V, where apparent cracks in the center of the microsphere are seen for the c-NCM811 (Figure E and Figure S16), while only subtle microcracks can be discovered in the r-NCM811 (Figure F and Figures S17–18). Even after 300 cycles, r-NCM811 also exhibits satisfactory sphericity and structure stability, a sharp contrast to the aggravated c-NCM811 (Figure S19).…”

Section: Resultsmentioning

confidence: 98%

Isotropic Microstrain Relaxation in Ni-Rich Cathodes for Long Cycling Lithium Ion Batteries

Wang,

Wei,

Han

et al. 2023

ACS Nano

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Developing isotropic-dominated microstrain relaxation is a vital step toward the enhancement of cyclic performance and thermal stability for high-energydensity Ni-rich cathodes. Here, a microstructure engineering strategy is employed for synthesizing the elongated primary particles radially aligned Ni-rich cathodes only by regulating the precipitation rates of cations and the distributions of flow field. The asobtained cathode also exhibits an enlarged lattice distance and highly exposed (003) plane. The high aspect ratio and favorable atomic arrangement of primary particles not only enable isotropic strain relaxation for effectively suppressing microcrack formation and propagation, but also facilitate Li-ion diffusion with greatly reduced Li/Ni mixing. Consequently, it shows obvious superiority in the high-rate, long-cycle life, and thermal stability compared with the conventional counterparts. After modification, an exceptionally long life is achieved with a capacity retention of 90.1% at 1C and 84.3% at 5C after 1500 cycles within 3.0−4.3 V in a 1.5-Ah pouch cell. This work offers a universal strategy to achieve isotropic strain distribution for conveniently enhancing the durability of Ni-rich cathodes.

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Section: Resultsmentioning

confidence: 98%

Isotropic Microstrain Relaxation in Ni-Rich Cathodes for Long Cycling Lithium Ion Batteries

Wang,

Wei,

Han

et al. 2023

ACS Nano

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“…The trend is consistent with the EIS testing results that 1%Nb-NM91 showed greatly reduced charge-transfer resistances at 1st, 100 th , and 150th cycles (Figure S16 and Table S4 in the Supporting Information), implying the improved electrochemical dynamics of NM91 after Nb doping. The improved electrochemical dynamics of LiNi 0.9 Mn 0.1 O 2 after Nb doping should be due to the expanded lattice volume that increased the volume of tetragonal interstitials between the LiO 6 octahedral and reduced Li + diffusion barrier. ,,− …”

Section: Resultsmentioning

confidence: 99%

Structural Reinforcement through High-Valence Nb Doping to Boost the Cycling Stability of Co-Free and Ni-Rich LiNi_0.9Mn_0.1O₂ Cathode Materials

Hu,

Ma,

et al. 2023

Energy Fuels

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As an important Co-free and Ni-rich layered oxide, LiNi 0.9 Mn 0.1 O 2 (NM91) has garnered significant interest as a promising cathode material for lithium-ion batteries. Despite its attractively high specific capacity, the intrinsic structural instability poses a great challenge to its electrochemical performances, especially cycling performance. In this work, we circumvent the structural instability issue of NM91 through high-valence Nb doping. Our findings reveal that high-valence Nb 5+ dopants were successfully incorporated into the lattice of LiNi 0.9 Mn 0.1 O 2 , functioning as interlayer pillars that reinforce the structure and mitigate the detrimental H2 → H3 phase transition. This results in greatly improved cycling stability and rate capability of the cathode. The discharge capacities of 1%Nb-NM91 reached 211.8 mA h g −1 at 0.1 C and 159.3 mA h g −1 at 5 C, with a retention rate of 95.6% after 100 cycles at 0.5 C, even superior to the previously reported lower Ni content counterparts, including LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , and so forth. This study demonstrates that highvalence Nb doping is a promising strategy to overcome the structural instability issue in LiNi 0.9 Mn 0.1 O 2 and underscores the potential of Co-free Ni-rich layered oxides as cathode materials for lithium-ion batteries.

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“…High-nickel cathode materials with high working potential and high specific capacity have also received widespread attention. [133][134][135][136] Chang's group [38] investigated the chemical and crystal structural evolutions of LiNi 0.83 Co 0.11 Mn 0.06 O 2 , a commercially-available high-Ni cathode material. The cathode material changes from a layered structure to a periodic cation-mixed spinel-like phase during constant-current, constant-voltage charging, which results in voltage hysteresis.…”

Section: Structural Evolutionmentioning

confidence: 99%

Voltage Hysteresis in Transition Metal Oxide Cathodes for Li/Na‐Ion Batteries

Liu

et al. 2023

Adv Funct Materials

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essential for the commercial application of Li/Na-ion batteries. The investigated cathode materials mainly include oxides, polyanion compounds, Prussian blue analogues, and organic salts. Among them, layered transition metal oxides contained in oxides are promising candidates due to their suitable operational potentials, 2D ions diffusion channels, and simple synthesis. Meanwhile, it was generally believed that to achieve a fast ions diffusion, the atomic configuration in the crystal structure of layered cathode materials must be well ordered. [7,8] However, this stereotype is now being reconsidered with the discovery of the percolation theory about 3D ions diffusion in a disordered rock-salt (DRX) structure. [9,10] This percolation occurs when Li-ions hop from one octahedral site to another through an intermediate tetrahedral site, where the Liions in the tetrahedral sites are identified as an active Li for the hopping. [11] In this regard, various new types of Li-rich DRX cathode materials with promising capacities (>250 mAh g −1 ) have been discovered. [12][13][14][15][16][17][18][19] Given their unique advantages, these oxide materials have attracted extensive attention from researchers worldwide.Although demonstrating a high capacity, application-wise, these oxide materials also exhibit voltage hysteresis and significant loss of energy density, since the voltage associated with this redox process on charge cannot be recovered on discharge, which represents a key challenge that inhibits exploiting the full potential of these materials. This voltage hysteresis persists throughout the electrochemical cycling, resulting in a continuous decrease of the average discharge voltage. Therefore, the understanding of voltage hysteresis is particularly important because it not only minimizes energy density and drastically reduces energy efficiency but also hinders further development and commercialization of Li/Na-ion batteries. When voltage hysteresis was discovered in LiFePO 4 materials in the early years, experimental limitations and the lack of a theoretical framework prevented researchers from drawing concrete conclusions about the phenomenon. With the development of increasingly sophisticated analytical techniques for studying voltage hysteresis, reassessing the understanding of the origin of voltage hysteresis can now be done from a mechanical perspective and even reveal new discoveries that were previously unavailable due to experimental limitations. [20]

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Strain Engineering of Ni‐Rich Cathode Enables Exceptional Cyclability in Pouch‐Type Full Cells

Cited by 47 publications

References 45 publications

Isotropic Microstrain Relaxation in Ni-Rich Cathodes for Long Cycling Lithium Ion Batteries

Isotropic Microstrain Relaxation in Ni-Rich Cathodes for Long Cycling Lithium Ion Batteries

Structural Reinforcement through High-Valence Nb Doping to Boost the Cycling Stability of Co-Free and Ni-Rich LiNi_0.9Mn_0.1O₂ Cathode Materials

Voltage Hysteresis in Transition Metal Oxide Cathodes for Li/Na‐Ion Batteries

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Strain Engineering of Ni‐Rich Cathode Enables Exceptional Cyclability in Pouch‐Type Full Cells

Cited by 47 publications

References 45 publications

Isotropic Microstrain Relaxation in Ni-Rich Cathodes for Long Cycling Lithium Ion Batteries

Isotropic Microstrain Relaxation in Ni-Rich Cathodes for Long Cycling Lithium Ion Batteries

Structural Reinforcement through High-Valence Nb Doping to Boost the Cycling Stability of Co-Free and Ni-Rich LiNi0.9Mn0.1O2 Cathode Materials

Voltage Hysteresis in Transition Metal Oxide Cathodes for Li/Na‐Ion Batteries

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Structural Reinforcement through High-Valence Nb Doping to Boost the Cycling Stability of Co-Free and Ni-Rich LiNi_0.9Mn_0.1O₂ Cathode Materials