| 초록 |
Cobalt-free layered lithium-rich nickel manganese oxides, Li[LixNiyMn1−x−y]O2, 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 is attributed to the irreversible structural rearrangement involving oxygen loss and cation migration, making these materials less practical. Herein, we demonstrate that substituting with Ni3+ as a redox buffer deactivates the Mn reduction by introducing an alternative redox path and significantly reduces the undesirable phase transformation, thereby resolving the voltage decay problem. Based on these findings, we propose a general strategy to suppress the voltage decay and achieve long-lasting high energy density from this class of materials. |
