Surface Modification Engineering Enabling 4.6 V Single-Crystalline Ni-Rich Cathode with Superior Long-Term Cyclability
Surface Modification Engineering Enabling 4.6 V Single-Crystalline Ni-Rich Cathode with Superior Long-Term Cyclability
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表面改性工程实现具有上级长期循环性能的4.6 V单晶富镍阴极
DOI：
10.1002/adfm.202109421
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发表时间：
2021-10-27
影响因子：
19
通讯作者：
Zheng, Jun-Chao
中科院分区：
文献类型：
--
作者：
Fan, Xin-Ming;Huang, Ying-De;Zheng, Jun-Chao
在层状过渡金属氧化物阴极（NCM）中增加镍和降低钴含量是实现商业锂离子电池中增加能量密度和成本竞争力的可行策略。然而，NCM阴极的实际长期循环由于不可逆的界面相变和不可避免的裂纹形成而遭受严重的容量退化。本文中，使用原位改性策略通过互连单晶层状LiNi0.6Co0.1Mn0.3O2（SC-NCM）颗粒来形成均匀且保形的Li1.8Sc0.8Ti1.2（PO 4）（3）（LSTP）保护层。LSTP表面改性有助于在阴极和电解质之间构建坚固的阴极-电解质界面薄膜，这可以防止电解质对SC-NCM的腐蚀，并且力学稳定性可以改善恶劣条件下长时间循环引起的晶间裂纹。此外，LSTP导电改性层促进了锂离子在阴极颗粒之间的传输，有效地提高了倍率性能。令人印象深刻的是，LSTP改性的SC-NCM在5C的高放电速率下表现出144.3 mAh g（-1）的高可逆容量，即使在4.6 V的超高充电电压下运行500次循环后，容量保持率仍保持在90.27%。此外，在袋型全电池中，石墨/LSTP改性的SC-NCM在1700次循环后保持89.6%的容量保持率。
Aiming for increased nickel and lower cobalt content in layered transition metal oxide cathodes (NCM) is a feasible strategy for achieving increased energy density and cost competitiveness in commercial lithium-ion batteries. However, the practical long-term cycling of NCM cathodes suffers from severe capacity degradation due to irreversible interface phase transformation and unavoidable crack formation. Herein, an in situ modification strategy is used to form a uniform and conformal Li1.8Sc0.8Ti1.2(PO4)(3) (LSTP) protective layer by interconnecting the single-crystal-layered LiNi0.6Co0.1Mn0.3O2 (SC-NCM) particles. LSTP surface modification helps to construct a robust cathode-electrolyte interphase thin film between the cathode and the electrolyte, which can prevent SC-NCM corrosion by electrolyte, and the stability of the mechanics can improve the intergranular cracks caused by long cycles under harsh conditions. Moreover, the LSTP conductive modification layer facilitates the lithium-ion transport among cathode particles, effectively enhancing the rate capability. Impressively, the LSTP modified SC-NCM exhibits a high reversible capacity of 144.3 mAh g(-1) at the high discharge rate of 5 C and maintains a capacity retention of 90.27% even at the ultrahigh charge voltage of 4.6 V operation after 500 cycles. Moreover, in a pouch-type full battery, the graphite/LSTP modified SC-NCM maintains a capacity retention of 89.6% after 1700 cycles.