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The exploration of a CuNb3O8 Li+-storage anode compound
Materials Technology ( IF 2.9 ) Pub Date : 2021-03-11 , DOI: 10.1080/10667857.2021.1898712
Cihui Huang 1, 2 , Renjie Li 3 , Lijie Luo 1 , Yongjun Chen 1 , Chunfu Lin 2
Affiliation  

ABSTRACT

Niobates are regarded as prospective Li+-storage anode candidates due to the rich chemistry of niobium and crystal-structural openness. However, the exploration of niobates is still insufficient. In this study, we explore CuNb3O8 with a large theoretical capacity is 341.9 mAh g–1 as a high-performance anode compound. The reversible redox reaction among Nb5+, Nb4+ and Nb3+ during lithiation/delithiation is confirmed by ex-situ XPS, and a large reversible capacity of 231.8 mAh g–1 and safe lithiation potential of 1.53 V are achieved at 0.1 C. An intercalation-type Li+-storage mechanism is confirmed by in-situ XRD after the first lithiation process, guaranteeing the good cyclability from the second discharge–charge cycles. The Li+ diffusivity in CuNb3O8 is systematically and carefully studied. The galvanostatic intermittent titration technique tests show large Li+ diffusion coefficients of 1.2 × 10–12/1.5 × 10–12 cm2 s–1 during lithiation/delithiation, and the corresponding values obtained through the cyclic voltammetry technique are similar (2.2 × 10–12/3.0 × 10–12 cm2 s–1). Additionally, CuNb3O8 is successfully coupled with LiFePO4, and the resultant CuNb3O8//LiFePO4 full cell also exhibits good electrochemical properties, demonstrating the practicability of CuNb3O8 for large-scale energy-storage applications.



中文翻译:

CuNb3O8 Li+-储存负极化合物的探索

摘要

由于铌的丰富化学性质和晶体结构的开放性,铌酸盐被认为是潜在的锂离子存储负极候选者。然而,铌酸盐的探索仍然不足。在本研究中,我们探索了具有大理论容量为 341.9 mAh g -1的 CuNb 3 O 8作为高性能负极化合物。异位XPS证实了锂化/脱锂过程中Nb 5+、Nb 4+和Nb 3+之间的可逆氧化还原反应,在0.1时实现了231.8 mAh g -1的大可逆容量和1.53 V的安全锂化电位C. 嵌入型 Li +-存储机制在第一次锂化过程后通过原位XRD 确认,保证了第二次放电-充电循环的良好循环性。对CuNb 3 O 8中的Li +扩散率进行了系统而仔细的研究。恒电流间歇滴定技术测试表明,锂化/脱锂过程中 Li +扩散系数为 1.2 × 10 –12 /1.5 × 10 –12 cm 2 s –1,通过循环伏安技术获得的相应值相似(2.2 × 10 –12 /3.0 × 10 –12厘米2–1)。此外,CuNb 3 O 8与LiFePO 4成功耦合,得到的CuNb 3 O 8 //LiFePO 4全电池也表现出良好的电化学性能,证明了CuNb 3 O 8在大规模储能应用中的实用性。

更新日期:2021-03-11
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