From Calendar Aging to Cycle Degradation: SOC-Dependent Structural and Interfacial Evolution in LiFePO₄/Graphite Batteries

TY - JOUR

T1 - From Calendar Aging to Cycle Degradation

T2 - SOC-Dependent Structural and Interfacial Evolution in LiFePO4/Graphite Batteries

AU - Jin, Yi

AU - Tang, Rui

AU - Shi, Qi

AU - Dong, Jinyang

AU - Wang, Zhiheng

AU - Guan, Yibiao

AU - Lu, Yun

AU - Yan, Kang

AU - Liu, Yun

AU - Li, Ning

AU - Qi, Qiongqiong

AU - Gao, Jiaxin

AU - Chen, Lai

AU - Wu, Feng

AU - Su, Yuefeng

N1 - Publisher Copyright: © 2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH.

PY - 2026/4/1

Y1 - 2026/4/1

N2 - This study investigates the impact of calendar aging conditions on the subsequent cycling performance of lithium-ion batteries. The experiments utilized LiFePO4/graphite (LFP/Gr) pouch cells, which were charged to two states of charge (SOC): 50% and 100%. After storage at 45 °C for 100 d, cycling aging tests were conducted. The results indicate that the pre-storage conditions significantly affect cycling stability: batteries stored at high SOC exhibited more severe capacity degradation and mechanical deterioration, whereas those stored at low SOC maintained better electrochemical reversibility and mechanical stability. Through a multiscale investigation, it was found that high SOC calendar aging induces side reactions at the electrode interface and promotes uneven formation of the solid electrolyte interphase (SEI) on the anode. The structural and chemical damages incurred during the storage process become potential failure sources and manifest during the cycling aging process. This research establishes a statistical correlation framework between calendar aging damage and cycling failure, suggesting that the performance degradation of lithium-ion batteries is not solely attributed to long-term cycling but is also significantly influenced by prior storage conditions. The findings provide important insights for optimizing SOC management and storage strategies to enhance battery lifespan and reliability.

AB - This study investigates the impact of calendar aging conditions on the subsequent cycling performance of lithium-ion batteries. The experiments utilized LiFePO4/graphite (LFP/Gr) pouch cells, which were charged to two states of charge (SOC): 50% and 100%. After storage at 45 °C for 100 d, cycling aging tests were conducted. The results indicate that the pre-storage conditions significantly affect cycling stability: batteries stored at high SOC exhibited more severe capacity degradation and mechanical deterioration, whereas those stored at low SOC maintained better electrochemical reversibility and mechanical stability. Through a multiscale investigation, it was found that high SOC calendar aging induces side reactions at the electrode interface and promotes uneven formation of the solid electrolyte interphase (SEI) on the anode. The structural and chemical damages incurred during the storage process become potential failure sources and manifest during the cycling aging process. This research establishes a statistical correlation framework between calendar aging damage and cycling failure, suggesting that the performance degradation of lithium-ion batteries is not solely attributed to long-term cycling but is also significantly influenced by prior storage conditions. The findings provide important insights for optimizing SOC management and storage strategies to enhance battery lifespan and reliability.

KW - Calendar aging

KW - Failure mechanism

KW - Interfacial chemistry

KW - LiFePO/graphite pouch cells

KW - Lithium inventory loss

KW - Phase transformation

KW - Solid electrolyte interphase

KW - State of charge

UR - https://www.scopus.com/pages/publications/105026043130

U2 - 10.1002/cjoc.70428

DO - 10.1002/cjoc.70428

M3 - Article

AN - SCOPUS:105026043130

SN - 1001-604X

VL - 44

SP - 931

EP - 938

JO - Chinese Journal of Chemistry

JF - Chinese Journal of Chemistry

IS - 7

ER -