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

Abstract

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.

Prussian Blue Analogues in Aqueous Batteries and Desalination Batteries

“…However, the excessive use of traditional energy produces carbon dioxide and other pollutants, causing serious ecological problems. To solve these environmental problems, scientists are beginning to explore renewable energy sources to reduce environmental pollution and meet the needs of social development [1][2][3][4][5]. However, these clean energy sources generally have the disadvantages of location dependence [6][7][8][9][10], high cost and low efficiency, which restrict their large-scale applications [11][12][13][14][15][16].…”

Recent Advances in Aqueous Batteries with Nonmetal Cations as Charge Carriers

“…Zhang et al also found an interesting hydrogen chemistry in CuHCF when NH 4 + inserted. [ 68 ] As discussed above, the excellent reversible performance of NH 4 + intercalation in PBAs has achieved. To excavate the mechanisms, a joint theoretical and experimental study were applied to analyze the results.…”

“…In their recent work, they studied the performance of NH 4 + intercalation in copper hexacyanoferrate (CuHCF), and there was nearly no capacity fading after 3000 cycles. Moreover, a new NH 4 + diffusion mechanism was proposed, [ 68 ] which was also discussed in the following section. Wang and co‐workers studied NH 4 + intercalation in emeraldine salt polyaniline (ES‐PANI).…”

Research Development on Aqueous Ammonium‐Ion Batteries

“…In Figure and Table 1 , we have summarized the various electrode materials and electrolytes used for aqueous AIBs. [ 78–101 ] Furthermore, we overview and discuss the research status of these systems.…”

“…[ 82,84 ] Most recently, Shu's team also explored three other new PBAs cathodes, Fe 4 [Fe(CN) 6 ] 3 (Fe‐PBs), (NH 4 ) 1.81 Cu II 0.8 Cu I 0.2 [Fe III 0.2 Fe II 0.8 (CN) 6 ] 0.95 (N‐CuHCF), and Cu 2.95 [Fe(CN) 6 ] 1.69 (Cu‐PBs), for aqueous ammonium‐ions storage. [ 90 92,93 ] For Cu‐PBs electrode, [ 93 ] a reversible capacity of 76 mAh g –1 and discharge plateau of ≈0.75 V (vs Ag/AgCl) with very small polarization can be achieved ( Figure A). Cu‐PBs also exhibited excellent rate capability and long‐term cycling performance: the reversible capacities are 76, 72, and 71 mAh g −1 at different current rates from 1, 35, to 50 C, corresponding capacity retention of as high as 93.4% at 50 C (Figure 5B); and high capacity retentions of 100% after 3000 cycles, 74.5% after 23 000 cycles and 72.5% over 30 000 cycles at 1 C, 30 C, and 50 C respectively.…”