Encapsulation of N-doped carbon layer via in situ dopamine polymerization endows nanostructured NaTi2(PO4)3 with superior lithium storage performance

Lee

Intl J of Energy Research

et al. 2022

Using platinum-based alloy nanocatalysts with other transition metals has the advantages of enhancing the oxygen reduction reaction (ORR) activity and reducing the platinum usage. However, there are many challenges to using nanocatalysts, including their instability, which hinder their practical application. In this study, we employed a strategy to improve the intrinsic instability of a nanocatalyst by encapsulating a dopamine-derived carbon layer on the surfaces of nanoparticles. The carbon layer formed on the surfaces of platinum-nickel (PtNi) nanoparticles demonstrated improved stability by inhibiting the nanoparticle growth, even during the heat treatment process. This could induce a high degree of alloying while minimizing the loss of surface area for the nanoparticles, which ensured an improved catalyst activity. Additionally, the PtNi nanocatalyst with the dopamine-derived carbon layer showed an improved performance and stability under long-term fuel cell operation conditions, thus proving the practicality of this strategy. The strategy developed in this study is not only a novel and facile approach to the synthesis of alloy catalysts, but also addresses the inherent instability of nanoparticles, which will encourage the practical use and commercialization of alloy nanocatalysts.

Section: Resultsmentioning

confidence: 99%

Section: Preparation Of Carbon Shell-coated Ptni Nanocatalystmentioning

confidence: 99%

Improved platinum‐nickel nanoparticles with dopamine‐derived carbon shells for proton exchange membrane fuel cells

Lee

Intl J of Energy Research

et al. 2022

“…On the one hand, NTP can provide large pore channels for Li + migration, which conduces to Li + diffusion kinetics. [ 41–44 ] On the other hand, it can also reduce the crystallinity of PVDF‐HFP and improve the ionic conductivity of the composite membrane by generating rapid ion migration paths at the interface between NTP particles and PVDF‐HFP. The flexible PHNTP coating endows the composite separator with good mechanical properties preventing short circuits and acts as a physical barrier of Li dendrite penetration.…”

Section: Introductionmentioning

confidence: 99%

Regulating Lithium Deposition Behaviors by Functional PVDF‐HFP/NaTi₂(PO₄)₃ Composite Separator

Shang

Zhou

et al. 2022

Adv Materials Inter

The unpredictable growth of lithium (Li) dendrite is one of the crux issues in the commercial application of the Li‐metal batteries (LMBs). Herein, a flexible PVDF‐HFP/LiClO4/NaTi2(PO4)3 (NTP) layer modified polypropylene (PP) separators are designed to achieve homogeneous nucleation and growth of Li. The introduction of NTP particles not only reduces the crystallinity of the polymer but also generates a rapid Li+ migration pathway at the interface, which is conducive to regulating the Li+ flux and guiding the uniform Li deposition by improving ionic conductivity. In addition, because of the high electrolyte wettability and the enhanced mechanical strength of the functionalized separator, the mass transport capability is promoted and the penetration of Li dendrite can be avoided. Consequently, the modified separators with 20 wt% NTP (PP@PHNTP‐20) endow Cu||Li batteries with an excellent average Coulombic efficiency of ≈99%. Furthermore, the long‐term reversible Li plating/stripping can be achieved in the Li symmetric battery, and the LiFePO4 (LFP) ||Li batteries with PP@PHNTP‐20 present high capacity retention and improved C‐rate performance in a carbonate‐based electrolyte without additives.

Multiscale structural NaTi₂(PO₄)₃ anode for sodium‐ion batteries with long cycle, high areal capacity, and wide operation temperature

Xu,

Yang,

Yan

et al. 2024

Carbon Energy

Though plenty of research has been conducted to improve the low intrinsic electronic conductivity of NASICON‐structured NaTi2(PO4)3 (NTP), realizing sodium‐ion batteries with high areal/volumetric capacity still remains a formidable challenge. Herein, a multiscale design from anode material to electrode structure is proposed to obtain a gadolinium‐ion‐doped and carbon‐coated NTP composite electrode (NTP‐Gd‐C), in which gadolinium ion doping, oxygen vacancy, optimized structure, N‐doped carbon coating, and bridging on the three‐dimensional network are simultaneously achieved. In the whole electrode, the excellent hierarchical electronic/ionic conductivity and structural stability are simultaneously improved via the synergistic optimization of NTP‐Gd‐C. As a result, excellent electrochemical performances of NTP‐Gd‐C electrode with a high areal/volumetric capacity of 1.0 mAh cm−2/142.8 mAh cm−3, high rate capability (58.3 mAh g−1 at 200 C), long cycle life (ultralow capacity fading of 0.004% per cycle under 10,000 cycles), and wide‐temperature electrochemical performances (97.0 mAh g−1 at 2 C under −20°C) are achieved. Moreover, the NTP‐Gd‐C//Na3V2(PO4)3/C full cell also delivers an excellent rate capacity of 42.0 mAh g−1 at 200 C and long‐term high‐capacity retention of 66.2% after 4000 cycles at 20 C.