Some Directions for Performance Improvement of Li-Ion Batteries out of Usual Paths

Recent developments at IMN will be shared on several research directions out of usual paths for performance improvement of Li-ion batteries. We will focus on innovative surface modifications of electrode components, new electrode compositions and architectures, and failure mechanism upon cycling by in-depth characterization through coupled advanced spectroscopic techniques. A molecular grafting approach has been proposed as a way to modify the interfacial chemical reactivity of oxide materials, which is detrimental to their long-term energy storage properties as electrodes of Li-ion batteries. Surface derivatization of powder oxide materials such as Li1.2V3O8 and Li(Mn,Ni)2O4 was accomplished by in situ electrografting of a diazonium salt during Li-ion intercalation, leading to a covalently bonded organic multilayer. Charge transfer is not impeded, while electrolyte decomposition is inhibited thus increasing the cycle life and decreasing the self-discharge. Carbon additives of classical porous electrodes occupy a large volume fraction which is lost for charge storage. Redox functionalization of the surface of some carbon additives has been successfully achieved through non-covalent grafting chemistry using multi-redox pyrene molecules synthesized on purpose. Such functionalized carbon additives have been used to increase the stored energy and power of C-coated LFP porous electrodes. Thicker electrodes are needed for higher energy density Li-ion batteries. We evaluate different directions in order to design new innovative electrode architectures for such a purpose. Our grafting chemistry has been further developed to achieve molecular junctions between non-carbon-coated LFP and multiwall carbon nanotubes (MWCNT) using a designed thiophene-based conjugated molecule. The strategy enables original architecturing of the cathode of Li-ion batteries, with the individual MWCNT being electronically nanocontacted at the surface of LFP grains. This advancement leads to much higher specific capacity and better capacity retention for non calendared thick electrodes, for which the electronic wiring of the electroactive material grains is a critical issue. Another direction followed is the use of conducting polymer additives in porous electrodes, which are able to act as both conducting fillers and mechanical reinforcement materials. We have synthesized a new form of lithium doped PANI, the excellent properties of which in terms of specific capacity, stability on cycling and rate capability will be presented. The coating of bare LFP particles with thin layers of this new Li-doped PANI allows surpassing the performance of commercial carbon coated LFP thick electrodes. The role of this PANI additive into millimetric thick electrodes of NMC material will also be discussed. Future developments of higher energy density Si-based Li-ion batteries depend on the mastering of side reactions at the Si anode. We will compare the SEI composition and morphology at the Si surface upon cycling in half cell and full Li-ion cell configurations using a combination of 7Li, 19F MAS NMR, XPS, TOF-SIMS and STEM-EELS. The origin of the much faster aging of Si-based full cells versus half cells and future directions for improvement will be discusse

Dietary phospholipids are more efficient than neutral lipids for long‐chain polyunsaturated fatty acid supply in European sea bass Dicentrarchus labrax larval development

International audienceAbstract We evaluated the effects of dietary lipid class (phospholipid vs. neutral lipid) and level of n−3 long‐chain PUFA (LC‐PUFA) on the growth, digestive enzymatic activity, and histological organization of the intestine and liver in European sea bass larvae. Fish were fed from the onset of exogenous feeding at 7 to 37 d post‐hatch with five isoproteic and isolipidic compound diets with different levels of EPA and DHA. Diet names indicated the percentage of EPA and DHA contained in the phospholipids (PL) and neutral lipids (NL), as follows: PL5, PL3, PL1, NL1, and NL3. Histological observations showed different patterns of lipid absorption and accumulation in the intestinal mucosa depending on the level and nature of the dietary lipid fraction. Fish fed high levels of neutral lipids (11%, NL3 diet: 2.6% of EPA+DHA in the NL fraction) showed large intracellular and intercellular lipid deposits in the anterior intestine, but no such lipid accumulation was detected when larvae were fed with low and moderate levels of EPA and DHA in the phospholipid and neutral lipid fractions of the diet (PL and NL1 diets). PL were preferentially absorbed in the postvalvular intestine, and the accumulation of marine PL was inversely correlated to their dietary level. The postvalvular intestinal mucosa and liver showed signs of steatosis; large lipid vacuoles were observed in this region of the intestine and in the liver and were inversely correlated with the level of dietary neutral lipids. The best results in terms of growth, survival, and development (maturation of the digestive system and histological organization of the liver and intestinal mucosa) were obtained in the group fed with 2.3% of EPA and DHA in the PL fraction of the diet (PL3 diet), revealing that European sea bass larvae use the LC‐PUFa contained in the PL fraction more efficiently than those from the NL fraction of the diet

Protein hydrolysate vs. fish meal in compound diets for 10-day old sea bass Dicentrarchus labrax larvae

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Sea bass (Dicentrarchus labrax) larvae fed different Artemia rations: growth, pancreas enzymatic response and development of digestive functions

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Amylase and trypsin responses to intake of dietary carbohydrate and protein depend on the developmental stage in sea bass (Dicentrarchus labrax) larvae

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Cloning of endothelin-1 (ET-1) from European sea bass (Dicentrarchus labrax) and its gene expression analysis in larvae with retinoic acid-induced malformations

International audienceIt is known in vertebrates that endothelin-1 (ET-1) plays a key role in morphogenesis whose expression level greatly influences the development of craniofacial malformations. In the present study, the complete cDNA fragment encoding a precursor of endothelin-1, the preproendothelin-1 (PPET1), was cloned by RACE-PCR from European sea bass. The cDNA encoded a 199 amino acid polypeptide that was composed of the “mature” and “big” ET-1. Relative ET-1 expression levels were investigated in European sea bass larvae fed microparticulate diets containing the standard amount (0.08 g retinol/kg diet: group N) or an excess of retinoic acid which induces skeletal malformations (0.5 g retinol/kg diet: group RA). Real-time reverse transcription polymerase chain reaction analysis revealed that PPET1 mRNA levels were sensitively reduced in the RA group during early development (days 10 and 15 post hatching). Regulation of ET-1 gene expression in larvae fed the teratogenic level of vitamin A confirmed the involvement of ET-1 in the molecular mechanism involved in craniofacial deformities. These results suggest that the expression level of ET-1 may be used as a precocious molecular marker to predict malformations during European sea bass development

Multiprobe Study of the Solid Electrolyte Interphase on Silicon-Based Electrodes in Full-Cell Configuration

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Dietary vitamin mix levels influence the ossification process in European sea bass ( Dicentrarchus labrax ) larvae

International audienceThe influence of dietary vitamins on growth, survival, and morphogenesis was evaluated until day 38 of posthatching life in European sea bass larvae ( Dicentrarchus labrax). A standard vitamin mix (VM), at double the concentration of the U.S. National Research Council's recommendations, was incorporated into larval feeds at 0.5%, 1.5%, 2.5%, 4.0%, and 8.0% to give treatments VM 0.5, VM 1.5, VM 2.5, VM 4.0, and VM 8.0, respectively. The group fed the VM 0.5 diet all died before day 30. At day 38, the larvae group fed VM 1.5 had 33% survival, while the other groups, with higher vitamin levels, showed at least 50% survival. The higher the percentage VM in the diet, the lower the percentage of column deformities. High dietary vitamin levels positively influenced the formation of mineralized bone in larvae: the higher the dietary vitamin level, the higher the ossification status. In the larvae group fed at the highest vitamin levels, we observed a temporal sequence of coordinated growth factor expression, in which the expression of bone morphometric protein (BMP-4) preceded the expression of IGF-1, which stimulated the maturation of osteoblasts (revealed by high osteocalcin expression levels). In groups fed lower proportions of vitamins, elevated proliferator peroxisome-activated receptors (PPAR-γ) expression coincided with low BMP-4 expression. Our results suggest that high levels of PPAR-γ transcripts in larvae-fed diets with a low VM content converted some osteoblasts into adipocytes during the first two weeks of life. This loss of osteoblasts is likely to have caused skeletal deformities

Evaluation of the impact of polyethylene microbeads ingestion in European sea bass (Dicentrarchus labrax) larvae

Microplastics are present in marine habitats worldwide and may be ingested by low trophic organisms such as fish larvae, with uncertain physiological consequences. The present study aims at assessing the impact of polyethylene (PE 10-45µM) microbeads ingestion in European sea bass (Dicentrarchus labrax) larvae. Fish were fed an inert diet including 0, 104 and 105 fluorescent microbeads per gram from 7 until 43 days post-hatching (dph). Microbeads were detected in the gastrointestinal tract in all fish fed diet incorporating PE. Our data revealed an efficient elimination of PE beads from the gut since no fluorescent was observed in the larvae after 48h depuration. While the mortality rate increased significantly with the amount of microbeads scored per larvae at 14 and 20 dph, only ingestion of the highest concentration slightly impacted mortality rates. Larval growth and inflammatory response through Interleukine-1-beta (IL-1) gene expression were not found to be affected while cytochrome-P450-1A1 (cyp1a1) expression level was significantly positively correlated with the number of microbeads scored per larva at 20 dph. Overall, these results suggest that ingestion of PE microbeads had limited impact on sea bass larvae possibly due to their high potential of egestio

The effects of dietary marine protein hydrolysates on the development of sea bass larvae, Dicentrarchus labrax, and associated microbiota

International audienceProtein hydrolysate is an essential component of dry starter diets for fish larvae, as promoting healthy development. Peptides are also suitable substrates for many intestinal microbes. Five experimental diets were compared to a control diet (CONT) supplemented with a commercial fish protein hydrolysate. Each diet contained one marine protein hydrolysate, which differed by the proportion of di- and tri-peptides, and by raw materials. Two diets (HYD4 and HYD5) stimulated larval growth compared with CONT. Two other diets (HYD1 and HYD2) yielded inferior growth. HYD1 was detrimental for survival, which was associated with an up-regulation of genes involved in inflammation and antioxidative responses, while the gene coding for osteocalcin was down-regulated in this group. The relative activity of enzymes in the brush border membrane of enterocytes was significantly stimulated with diets HYD3 and HYD4. Gut microbiota were influenced by the diet, but the bacterial community profiles observed with HYD3 and HYD4 were the only ones that were not significantly dissimilar. Groups HYD1 and HYD2 showed the most dissimilar microbiota. It was concluded that the nature of the marine protein hydrolysate is important for larval development and health, but a high proportion of small peptides is not a sufficient criterion to assess dietary valu