LiPF<sub>6 </sub>as Effective Etching Agent of LiMnPO<sub>4 </sub>colloidal Nanocrystals for High Rate Li-Ion Battery Cathodes
Bibliographic record
Abstract
LiMnPO4 is an attractive cathode material for the next-generation high power Li-ion batteries, due to its high theoretical specific capacity (170 mA h g−1) and working voltage (4.1 V vs Li+/Li). Two main drawbacks prevent the practical use of LiMnPO4: (i) its low electronic conductivity and (ii) the limited lithium diffusion rate, responsible for the poor rate capability of the cathode. The use of nano-particles can alleviate the issues associated with poor ionic conductivity while the electronic resistance is usually lowered by coating the particles with a carbon layer. It is therefore of primary importance to develop a synthetic route to LiMnPO4 nanocrystals (NCs) with controlled size and coated with a highly conductive carbon layer. Here we report an effective surface etching process (using LiPF6) on colloidally synthesized LiMnPO4 NCs that makes the NCs more hydrophilic and dispersible in the aqueous glucose solution used as carbon source for the carbon coating step. The carbon coated etched LiMnPO4-based electrode exhibited a specific capacity of 118 mA h g−1 at 1C, with a stable cycling performance and a capacity retention of 92% after more than 100 cycles at different C-rates. The delivered capacities were higher than those of not etched carbon coated NCs, which never exceeded 30 mA h g−1. The adopted etching process allowed: (i) The efficient removal of the hydrophobic passivated surfactants shell, present on NCs surface after the colloidal synthesis. This increases the nanoparticles’ solubility in the aqueous glucose solution used as carbon source for NCs coating, enabling the formation of a good conductive carbon layer. (ii) The possibility to prepare composite electrodes with a reduced amount of carbon additive and polymeric binder (less than 20% wt. in total), with a consequent benefit on the energy density of LMP-based cathodes. The protocol reported here enabled the preparation of LMP/NCs-based cathodes with high rate capability and which can be charged with a fast CC−CV procedure (of maximum 2 h at 1C-rate), which is of paramount importance for the future development of high rate and high power Li-ion batteries.
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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 | 0.000 |
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".