LiNi<sub>0.6</sub>Mn<sub>0.2</sub>Co<sub>0.2</sub>O<sub>2</sub> Dry-Coated with Nano- Alumina As Positive Electrode Material
Bibliographic record
Abstract
Applications of lithium ion batteries in grid storage and electric vehicle require long lifetime. Surface coating of active material is an effective way to improve the long-term cycling of lithium ion batteries.1 Most of the coating methods reported so far are wet-coating method, which produces waste liquid and requires additional drying process. In this study, LiNi0.6Mn0.2Co0.2O2 was coated with nano-alumina using a convenient dry-coating method and characterized in Li cells. Commercial LiNi0.6Mn0.2Co0.2O2 powders (obtained from Umicore) were mixed with 3% Al2O3 (13 nm, from Sigma-Aldrich) using a dry-coating method. For comparison, LiNi0.6Mn0.2Co0.2O2 powders were also mixed with 3% Al2O3 by hand-grinding. Electrodes were made with active material, PVDF binder, carbon black at a ratio of 86:7:7 and dried under vacuum at 120 ℃ overnight. 1M LiPF6 in a solution of EC and DEC (volume ratio 1:2) was used as electrolyte and Li foil was used as counter/reference electrode. Figure 1(a) shows the SEM image of LiNi0.6Mn0.2Co0.2O2 powders. Secondary particles with spherical morphology were observed. The average particle size is ~1 μm for primary particle and ~10 μm for secondary particle. Figure 1(b) shows the SEM image of LiNi0.6Mn0.2Co0.2O2 powders coated with 3% Al2O3 using the dry coating method. Figure 1(c) shows the SEM image of LiNi0.6Mn0.2Co0.2O2 powders mixed with 3% Al2O3 by hand-grinding. The dry coating method produced a more homogeneous and dense coating, compared to materials produced by hand-grinding. Figure 2 shows the cycling performance at C/2 for all the materials cycled between 3 V – 4.4 V. Compared to pristine NMC 622, the materials processed with 3% Al2O3 displayed lower reversible capacity. However, the cycling performance was improved for both materials. Notably, materials dry-coated with 3% Al2O3 showed little capacity fade in 50 cycles. This study gives an example of using dry coating method for improving the cycling performance of positive electrode materials for lithium ion batteries. References Z. Chen et al., J. Mater. Chem., 20, 7606-7612 (2010) Figure 1
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".