Copper hexacyanoferrate as ultra-high rate host for aqueous ammonium ion storage

Zhang, Xikun; Xia, Maoting; Liu, Tingting; Peng, Na; Yu, Haoxiang; Zheng, Runtian; Zhang, Liyuan; Shui, Miao; Shu, Jie

doi:10.1016/j.cej.2020.127767

Cited by 87 publications

(111 citation statements)

References 72 publications

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“…[43,44] Similarly, in the case of Co 2p and Cu 2p, (shake-up) satellite peaks were detected at 786 and 802 eV and at 944 and 964 eV, respectively, indicating the presence of Co 2+ [45,46] and Cu 2+ . [14,47] Two additional peaks at 933.0 and 952.9 eV appeared in the Cu 2p spectrum, corresponding to Cu 1+ 2p 3/2 and Cu 1+ 2p 1/2 , respectively. [14,47] This finding suggests that an internal redox reaction from Cu 2+ to Cu 1+ occurred during the synthesis, accompanied by partial oxidation of Ni 2+ to Ni 3+ .…”

Section: Resultsmentioning

confidence: 99%

“…[14,47] Two additional peaks at 933.0 and 952.9 eV appeared in the Cu 2p spectrum, corresponding to Cu 1+ 2p 3/2 and Cu 1+ 2p 1/2 , respectively. [14,47] This finding suggests that an internal redox reaction from Cu 2+ to Cu 1+ occurred during the synthesis, accompanied by partial oxidation of Ni 2+ to Ni 3+ . Nevertheless, the average oxidation state of both the carbon-coordinated Fe 1 and nitrogen-coordinated M (Fe 2 , Mn, Ni, Cu and Co) cations is 2+, as expected for the PB structure with linear chains of Fe 2+  C≡NM 2+ N≡CFe 2+ .…”

Section: Resultsmentioning

confidence: 99%

“…The Ni 2p data (pristine state) revealed a larger fraction of trivalent Ni (858.6 eV) due to surface oxidation of Ni 2+ during electrode preparation at ambient conditions (despite strong overlapping with the satellite peak). [44] The Fe 2p, Mn 2p, and Co 2p spectra showed clear signs of partial oxidation of Fe 2+ to Fe 3+ (710.9 eV), [47,57] Mn 2+ to Mn 3+ (644.9 eV), [39] and Co 2+ to Co 3+ (780.6 eV) [45,58] after the charge cycle (desodiation). Interestingly, Cu existed in a purely divalent state (935.1 eV), indicating that Cu 1+ is getting oxidized to Cu 2+ upon charging.…”

Section: (4 Of 10)mentioning

confidence: 99%

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High‐Entropy Metal–Organic Frameworks for Highly Reversible Sodium Storage

et al. 2021

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Prussian blue analogues (PBAs) are reported to be efficient sodium storage materials because of the unique advantages of their metal–organic framework structure. However, the issues of low specific capacity and poor reversibility, caused by phase transitions during charge/discharge cycling, have thus far limited the applicability of these materials. Herein, a new approach is presented to substantially improve the electrochemical properties of PBAs by introducing high entropy into the crystal structure. To achieve this, five different metal species are introduced, sharing the same nitrogen‐coordinated site, thereby increasing the configurational entropy of the system beyond 1.5R. By careful selection of the elements, high‐entropy PBA (HE‐PBA) presents a quasi‐zero‐strain reaction mechanism, resulting in increased cycling stability and rate capability. The key to such improvement lies in the high entropy and associated effects as well as the presence of several active redox centers. The gassing behavior of PBAs is also reported. Evolution of dimeric cyanogen due to oxidation of the cyanide ligands is detected, which can be attributed to the structural degradation of HE‐PBA during battery operation. By optimizing the electrochemical window, a Coulombic efficiency of nearly 100% is retained after cycling for more than 3000 cycles.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: (4 Of 10)mentioning

confidence: 99%

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High‐Entropy Metal–Organic Frameworks for Highly Reversible Sodium Storage

et al. 2021

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“…According to the comparison between reported aqueous batteries, it is not difficult to find that present researches mainly focus on metallic carriers [ 9 – 13 ]. Nevertheless, proton (H + ), hydronium (H 3 O + ), and ammonium (NH 4 + ) as inexpensive and sustainable nonmetallic carriers have rarely been studied [ 14 – 16 ]. In recent years, although some electrode materials that can be resided for H + and H 3 O + , such as MoO 3 and WO 3 [ 17 , 18 ], have been reported, their further applications are severely restricted due to the strong acidity of the electrolyte, which leads to strong corrosion of electrode materials and severe side reactions of hydrogen evolution [ 19 – 21 ].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Bond-Assisted Ultra-Stable and Fast Aqueous NH4+ Storage

et al. 2021

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Aqueous ammonium ion batteries are regarded as eco-friendly and sustainable energy storage systems. And applicable host for NH4+ in aqueous solution is always in the process of development. On the basis of density functional theory calculations, the excellent performance of NH4+ insertion in Prussian blue analogues (PBAs) is proposed, especially for copper hexacyanoferrate (CuHCF). In this work, we prove the outstanding cycling and rate performance of CuHCF via electrochemical analyses, delivering no capacity fading during ultra-long cycles of 3000 times and high capacity retention of 93.6% at 50 C. One of main contributions to superior performance from highly reversible redox reaction and structural change is verified during the ammoniation/de-ammoniation progresses. More importantly, we propose the NH4+ diffusion mechanism in CuHCF based on continuous formation and fracture of hydrogen bonds from a joint theoretical and experimental study, which is another essential reason for rapid charge transfer and superior NH4+ storage. Lastly, a full cell by coupling CuHCF cathode and polyaniline anode is constructed to explore the practical application of CuHCF. In brief, the outstanding aqueous NH4+ storage in cubic PBAs creates a blueprint for fast and sustainable energy storage.

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“…Meanwhile, FeHCF has the advantages of low cost, environmental friendliness, and easy synthesis. Moreover, based on the "common ion effect", [42][43][44][45][46][47] Fe 2 (SO 4 ) 3 is added as a functional additive into the NH 4 (SO 4 ) 2 electrolyte in this work mainly to improve the cycling stability of AIBs. More details will be discussed below.…”

Section: Introductionmentioning

confidence: 99%