Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells
<p>Ni-rich lithium nickel manganese cobalt (NMC) oxide cathode materials promise Li-ion batteries with increased energy density and lower cost. However, higher Ni content is accompanied by accelerated degradation and thus poor cycle lifetime, with the underl...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
American Chemical Society
2022
|
| _version_ | 1797108937578774528 |
|---|---|
| author | Bjorklund, E Xu, C Dose, W Sole, C Thakur, P Lee, T-L De Volder, M Grey, C Weatherup, RS |
| author_facet | Bjorklund, E Xu, C Dose, W Sole, C Thakur, P Lee, T-L De Volder, M Grey, C Weatherup, RS |
| author_sort | Bjorklund, E |
| collection | OXFORD |
| description | <p>Ni-rich lithium nickel manganese cobalt (NMC) oxide cathode materials promise Li-ion batteries with increased energy density and lower cost. However, higher Ni content is accompanied by accelerated degradation and thus poor cycle lifetime, with the underlying mechanisms and their relative contributions still poorly understood. Here, we combine electrochemical analysis with surface-sensitive X-ray photoelectron and absorption spectroscopies to observe the interfacial degradation occurring in LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>O<sub>2</sub>–graphite full cells over hundreds of cycles between fixed cell voltages (2.5–4.2 V). Capacity losses during the first ∼200 cycles are primarily attributable to a loss of active lithium through electrolyte reduction on the graphite anode, seen as thickening of the solid-electrolyte interphase (SEI). As a result, the cathode reaches ever-higher potentials at the end of charge, and with further cycling, a regime is entered where losses in accessible NMC capacity begin to limit cycle life. This is accompanied by accelerated transition-metal reduction at the NMC surface, thickening of the cathode electrolyte interphase, decomposition of residual lithium carbonate, and increased cell impedance. Transition-metal dissolution is also detected through increased incorporation into and thickening of the SEI, with Mn found to be initially most prevalent, while the proportion of Ni increases with cycling. The observed evolution of anode and cathode surface layers improves our understanding of the interconnected nature of the degradation occurring at each electrode and the impact on capacity retention, informing efforts to achieve a longer cycle lifetime in Ni-rich NMCs.</p> |
| first_indexed | 2024-03-07T07:33:28Z |
| format | Journal article |
| id | oxford-uuid:7db99602-77ee-405f-a6b0-32a16cbf1bfa |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:33:28Z |
| publishDate | 2022 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:7db99602-77ee-405f-a6b0-32a16cbf1bfa2023-02-20T15:44:49ZCycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cellsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:7db99602-77ee-405f-a6b0-32a16cbf1bfaEnglishSymplectic ElementsAmerican Chemical Society2022Bjorklund, EXu, CDose, WSole, CThakur, PLee, T-LDe Volder, MGrey, CWeatherup, RS<p>Ni-rich lithium nickel manganese cobalt (NMC) oxide cathode materials promise Li-ion batteries with increased energy density and lower cost. However, higher Ni content is accompanied by accelerated degradation and thus poor cycle lifetime, with the underlying mechanisms and their relative contributions still poorly understood. Here, we combine electrochemical analysis with surface-sensitive X-ray photoelectron and absorption spectroscopies to observe the interfacial degradation occurring in LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>O<sub>2</sub>–graphite full cells over hundreds of cycles between fixed cell voltages (2.5–4.2 V). Capacity losses during the first ∼200 cycles are primarily attributable to a loss of active lithium through electrolyte reduction on the graphite anode, seen as thickening of the solid-electrolyte interphase (SEI). As a result, the cathode reaches ever-higher potentials at the end of charge, and with further cycling, a regime is entered where losses in accessible NMC capacity begin to limit cycle life. This is accompanied by accelerated transition-metal reduction at the NMC surface, thickening of the cathode electrolyte interphase, decomposition of residual lithium carbonate, and increased cell impedance. Transition-metal dissolution is also detected through increased incorporation into and thickening of the SEI, with Mn found to be initially most prevalent, while the proportion of Ni increases with cycling. The observed evolution of anode and cathode surface layers improves our understanding of the interconnected nature of the degradation occurring at each electrode and the impact on capacity retention, informing efforts to achieve a longer cycle lifetime in Ni-rich NMCs.</p> |
| spellingShingle | Bjorklund, E Xu, C Dose, W Sole, C Thakur, P Lee, T-L De Volder, M Grey, C Weatherup, RS Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells |
| title | Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells |
| title_full | Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells |
| title_fullStr | Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells |
| title_full_unstemmed | Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells |
| title_short | Cycle-induced interfacial degradation and transition metal cross-over in LiNi0.8Mn0.1Co0.1O2-graphite cells |
| title_sort | cycle induced interfacial degradation and transition metal cross over in lini0 8mn0 1co0 1o2 graphite cells |
| work_keys_str_mv | AT bjorklunde cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT xuc cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT dosew cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT solec cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT thakurp cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT leetl cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT devolderm cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT greyc cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells AT weatheruprs cycleinducedinterfacialdegradationandtransitionmetalcrossoverinlini08mn01co01o2graphitecells |