Suppression of Voltage Decay through Manganese Deactivation and Nickel Redox Buffering in HighEnergy Layered LithiumRich Electrodes
- Suppression of Voltage Decay through Manganese Deactivation and Nickel Redox Buffering in HighEnergy Layered LithiumRich Electrodes
- 홍지현; 구교진; 김형섭; 박혁준; 성원모; 정성균; 윤갑인; 박규영; 김해겸; 강기석
- Issue Date
- Advanced Energy Materials
- VOL 8, NO 21, 1800606
- Cobalt-free layered lithium-rich nickel manganese oxides, Li[LixNiyMn1-x-y]O-2 (LLNMO), are promising positive electrode materials for lithium rechargeable batteries because of their high energy density and low materials cost. However, substantial voltage decay is inevitable upon electrochemical cycling, which makes this class of materials less practical. It has been proposed that undesirable voltage decay is linked to irreversible structural rearrangement involving irreversible oxygen loss and cation migration. Herein, the authors demonstrate that the voltage decay of the electrode is correlated to Mn4+/Mn3+ redox activation and subsequent cation disordering, which can be remarkably suppressed via simple compositional tuning to induce the formation of Ni3+ in the pristine material. By implementing our new strategy, the Mn4+/Mn3+ reduction is subdued by an alternative redox reaction involving the use of pristine Ni3+ as a redox buffer, which has been designed to be widened from Ni3+/Ni4+ to Ni2+/Ni4+, without compensation for the capacity in principle. Negligible change in the voltage profile of modified LLNMO is observed upon extended cycling, and manganese migration into the lithium layer is significantly suppressed. Based on these findings, we propose a general strategy to suppress the voltage decay of Mn-containing lithium-rich oxides to achieve long-lasting high energy density from this class of materials.
- Appears in Collections:
- KIST Publication > Article
- Files in This Item:
There are no files associated with this item.
- RIS (EndNote)
- XLS (Excel)
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.