title: Origin of voltage decay in high-capacity layered oxide electrodes.
abstract: Although Li-rich layered oxides (Li1+xNiyCozMn1-x-y-zO2 > 250 mAh g(-1)) are attractive electrode materials providing energy densities more than 15% higher than today's commercial Li-ion cells, they suffer from voltage decay on cycling. To elucidate the origin of this phenomenon, we employ chemical substitution in structurally related Li2RuO3 compounds. Li-rich layered Li2Ru1-yTiyO3 phases with capacities of ~240 mAh g(-1) exhibit the characteristic voltage decay on cycling. A combination of transmission electron microscopy and X-ray photoelectron spectroscopy studies reveals that the migration of cations between metal layers and Li layers is an intrinsic feature of the charge-discharge process that increases the trapping of metal ions in interstitial tetrahedral sites. A correlation between these trapped ions and the voltage decay is established by expanding the study to both Li2Ru1-ySnyO3 and Li2RuO3; the slowest decay occurs for the cations with the largest ionic radii. This effect is robust, and the finding provides insights into new chemistry to be explored for developing high-capacity layered electrodes that evade voltage decay.
authors.affiliation: 1] FRE 3677 'Chimie du Solide et de l'Energie', Collège de France, 11, Place Marcelin Berthelot 75231 Paris, France [2] LRCS, CNRS UMR 7314, Université de Picardie Jules Verne, 80039 Amiens, France [3] ALISTORE-European Research Institute, 80039 Amiens, France.
authors.forename: M
authors.initials: M
authors.lastname: Sathiya
authors.affiliation: EMAT, University of Antwerp, Groenenborgerlaan 171 B-2020 Antwerp, Belgium.
authors.forename: A M
authors.initials: AM
authors.lastname: Abakumov
authors.affiliation: 1] ALISTORE-European Research Institute, 80039 Amiens, France [2] IPREM/ECP (UMR 5254), University of Pau, 2 av. Pierre Angot 64053 Pau Cedex 9, France [3] Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France.
authors.forename: D
authors.initials: D
authors.lastname: Foix
authors.affiliation: 1] FRE 3677 'Chimie du Solide et de l'Energie', Collège de France, 11, Place Marcelin Berthelot 75231 Paris, France [2] Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France [3] Sorbonne Universités UPMC Univ Paris 06, 4 place Jussieu 75252 Paris Cedex 05, France.
authors.forename: G
authors.initials: G
authors.lastname: Rousse
authors.affiliation: CSIR- CECRI- Chennai Centre, CSIR Campus, Taramani, Chennai-600 113, India.
authors.forename: K
authors.initials: K
authors.lastname: Ramesha
authors.affiliation: 1] ALISTORE-European Research Institute, 80039 Amiens, France [2] Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France [3] Institut Charles Gerhardt, CNRS UMR5253, Université Montpellier 2, 34 095 Montpellier, France.
authors.forename: M
authors.initials: M
authors.lastname: Saubanère
authors.affiliation: 1] ALISTORE-European Research Institute, 80039 Amiens, France [2] Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France [3] Institut Charles Gerhardt, CNRS UMR5253, Université Montpellier 2, 34 095 Montpellier, France.
authors.forename: M L
authors.initials: ML
authors.lastname: Doublet
authors.affiliation: Univ. Lille Nord de France, CNRS, UMR 8516 - LASIR, Univ. Lille 1, F-59655 Villeneuve d'Ascq, France.
authors.forename: H
authors.initials: H
authors.lastname: Vezin
authors.affiliation: CSIR- CECRI- Chennai Centre, CSIR Campus, Taramani, Chennai-600 113, India.
authors.forename: C P
authors.initials: CP
authors.lastname: Laisa
authors.affiliation: 1] FRE 3677 'Chimie du Solide et de l'Energie', Collège de France, 11, Place Marcelin Berthelot 75231 Paris, France [2] CSIR- CECRI- Chennai Centre, CSIR Campus, Taramani, Chennai-600 113, India.
authors.forename: A S
authors.initials: AS
authors.lastname: Prakash
authors.affiliation: 1] ALISTORE-European Research Institute, 80039 Amiens, France [2] IPREM/ECP (UMR 5254), University of Pau, 2 av. Pierre Angot 64053 Pau Cedex 9, France [3] Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France.
authors.forename: D
authors.initials: D
authors.lastname: Gonbeau
authors.affiliation: EMAT, University of Antwerp, Groenenborgerlaan 171 B-2020 Antwerp, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: VanTendeloo
authors.affiliation: 1] FRE 3677 'Chimie du Solide et de l'Energie', Collège de France, 11, Place Marcelin Berthelot 75231 Paris, France [2] ALISTORE-European Research Institute, 80039 Amiens, France [3] Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France.
authors.forename: J-M
authors.initials: JM
authors.lastname: Tarascon