Enhanced Potassium Storage Performance for K-Te Batteries <i>via</i> Electrode Design and Electrolyte Salt Chemistry

Zhang, Yue; Liu, Chang; Wu, Zhenrui; Manaig, Dan; Freschi, Donald J.; Wang, Zhen‐Bo; Liu, Jian

doi:10.1021/acsami.1c01155

Cited by 20 publications

(23 citation statements)

References 61 publications

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“…The large specific capacity difference between 1st and 2nd might be due to the formation of solid electrolyte interphase. [15] Regardless, Figure S8 (Supporting Information) validates the applicability of our CGPE in K-Te battery system.…”

Section: Resultssupporting

confidence: 64%

“…C 1s spectra could be decomposed into three peaks at 289.5, 285.0, and 283.6 eV, attributed to OCO, COC, and CC, respectively. [15] The existence of CO and CO bonds is confirmed by the peaks at 532.0 and 531.1 eV in O 1s spectra (Figure 3e). The intense peak at 686.7 eV and the weak peak at 682.0 eV are assigned to SF and KF bonds, respectively, originating from the KFSI salt.…”

Section: Resultsmentioning

confidence: 70%

“…illustrate a uniform surface and compact cross-section area. This great structural stability might benefit from the passivation of the KF-rich SEI layer, [4,15] which is confirmed by the energydispersive X-ray spectroscopy (EDS) mapping (Figure 7i) and the intense KF peak in XPS spectrum (Figure 7j). It should be noted that the thickness and interface in Figure 7h is different from Figure 2h, which could be due to pressure and SEI layer formation.…”

Section: Resultsmentioning

confidence: 70%

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Polyacrylonitrile‐Reinforced Composite Gel Polymer Electrolytes for Stable Potassium Metal Anodes

Zhang

Bahi

et al. 2022

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The potassium‐ion battery (PIB) is an emerging energy storage technology due to its potential low cost and reasonably high energy density. However, PIB suffers from severe potassium (K) dendrites growth and even short circuiting caused by the high reactivity of K metal. To address these challenges, this work develops a robust composite gel polymer electrolyte (CGPE), named poly(vinylidene fluoride‐hexafluoropropylene) potassium bis(fluorosulfonyl)imide polyacrylonitrile (PVDF‐HFP‐KFSI@PAN). It is found that the introduction of PAN nanofibers not only improves the mechanical properties but also widens the electrochemical stability window of the CGPE. As a result, the CGPE is much more effective in regulating K stripping/plating and enabling stable K metal anode. K metal symmetrical cells with CGPE exhibit a lifetime of over 1200 h at the current density of 0.5 mA cm−2, in contrast to 22 h for PVDF‐HFP‐KFSI and 185 h for a conventional glass fiber separator. The main reasons for the excellent performance of K metal cells with CGPE are attributed to the suppressed K dendrite growth, good structural integrity electrochemical stability of the CGPE, and stable KF‐rich solid electrolyte interphase layer at the electrode‐CGPE interface. It is expected that this facile strategy to stabilize K metal will pave the way for safer and more durable K metal batteries.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 70%

Section: Resultsmentioning

confidence: 70%

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Polyacrylonitrile‐Reinforced Composite Gel Polymer Electrolytes for Stable Potassium Metal Anodes

Zhang

Bahi

et al. 2022

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“…Moreover, the pore structure is critical in affecting K‐ion storage capacity and reaction pathways for K‐Te batteries. Our group reported a Te/C cathode with activated carbon (ASAC25) as the Te host and this Te/ASAC25 cathode possessed only one pair of anodic/cathodic peaks in the same voltage range of 0.5–3 V, [ 36 ] suggesting a one‐step electrochemical conversion from Te to K 2 Te or K 5 Te 3 . This Te/ASAC25 showed stable cycling performance without significant capacity fading after 100 cycles at 0.2 C because of the effective Te confinement by highly microporous carbon.…”

Section: Resultsmentioning

confidence: 99%

“…The excellent cycling stability was achieved with a specific capacity of 215.5 mAh g −1 after 100 cycles at 5C due to the superb immobilization of Te nanoparticles on the G‐CNT matrix. On the other hand, Liu et al [ 36 ] reported an enhanced K‐Te battery via rational design and electrolyte chemistry. Potassium hexafluorophosphate (KPF 6 ) was found to facilitate electron transfer and K‐ion diffusion, thus boosting redox kinetics and K‐ion storage performance.…”

Section: Introductionmentioning

confidence: 99%

High‐Performance Potassium‐Tellurium Batteries Stabilized by Interface Engineering

Zhang

Zhu

Freschi³

et al. 2022

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K/K + (−2.93 V versus standard hydrogen potential). [7] These advantages have promoted a fast research development of PIB over the past few years, primarily focusing on anode/cathode materials and electrolyte design. [8][9][10][11][12][13][14] Currently, high-voltage (2-4 V) cathode materials are receiving intense attention, [15] such as Prussian blue analogues, [16] layered metal oxides, [9,17,18] polyanionic compounds, [19] and organic cathodes. [20,21] One big challenge of these cathodes is the relatively low capacity of less than 180 mAh g −1 , which drags down the overall energy density of a full cell. [22] Conversion-type sulfur (S) or selenium (Se) is expected to realize a high theoretical capacity of 1675 and 675 mAh g −1 , respectively. [23][24][25] However, the newly emerging K-S or K-Se batteries deliver unsatisfying capacity far away from their ideal value in practical applications, which was mainly caused by the dissolution of polysulfies/ polyselenides intermediates and poor electrical conductivity of S (5 × 10 −28 S cm −1 ) and Se (5 × 10 −3 S cm −1 ). [26,27] Poor electric conductivity results in sluggish reaction kinetics, low utilization of active materials, severe capacity decay, and unsatisfying rate performance. [28,29] Tellurium (Te), another chalcogen element, possesses an excellent electrical conductivity of 2 × 10 2 S cm −1 and a high volumetric capacity of 2621 mAh cm −3 (specific capacity of 420 mAh g −1 ), showing great potential as cathode materials for lithium/sodium-ion storage. [30,31] Sun et al. [32] pioneered the study of Te cathodes in PIB with an average potential of 1.6 V in 2020. They revealed a stepwise reaction mechanism (Te ↔ K 2 Te 3 ↔ K 5 Te 3 ) in the ether-based electrolyte (KTFSI in DEGDME). The major issues for this K-Te battery system were low discharge capacity and rapid capacity fading, probably caused by the large volume change of Te and the dissolution of polytellurides during cycling. [33,34] By increasing electrolyte concentration from 1 M to 5 m KTFSI in DEGDME, the battery delivered a higher capacity up to 409 mAh g −1 . However, severe capacity decay still occurred, which requires rational cathode structure design to confine the acute volume change of Te. Guo et al. [35] disclosed the K-ion storage mechanism of Te cathode in the carbonate-based electrolyte (1 m KFSI in EC:DEC) with K 2 Te as the final potassiation product via a two-electron reaction (2 K + Te ↔ K 2 Te). The excellent cycling stability was achieved with a specific capacity of 215.5 mAh g −1 after 100 cycles at 5C due to the superb immobilization of Te nanoparticles on the The emerging potassium-tellurium (K-Te) battery system is expected to realize fast reaction kinetics and excellent rate performance due to the exceptional electrical conductivity of Te. However, there has been a lack of fundamental knowledge about this new K-Te system, including the reaction mechanism and cathode structure design. Herein, a two-step reaction pathway from Te to K 2 Te 3 and ultimately to K 5 Te 3 is investig...

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Dynamic Reversible Evolution of Solid Electrolyte Interface in Nonflammable Triethyl Phosphate Electrolyte Enabling Safe and Stable Potassium‐Ion Batteries

Ji¹,

Li²,

Song

et al. 2022

Adv Funct Materials

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Potassium-ion batteries (PIBs) are a favorable alternative to lithium-ion batteries (LIBs) for the large-scale electrochemical storage devices because of the high natural abundance of potassium resources. However, conventional PIB electrodes usually exhibit low actual capacities and poor cyclic stability due to the large radius of potassium ions (1.39 Å). In addition, the high reactivity of potassium metal raises serious safety concerns. These characteristics seriously inhibit the practical use of PIB electrodes. Here, zinc phosphide composites are rationally designed as PIB anodes for operation in a nonflammable triethyl phosphate (TEP) electrolyte to solve the above-mentioned issues. The optimized zinc phosphide composite with 20 wt% zinc phosphate presents a high specific capacity (571.1 mA h g −1 at 0.1 A g −1 ) and excellent cycling performance (484.9 mA h g −1 with the capacity retention of 94.5% after 1000 cycles at 0.5 A g −1 ) in the KFSI-TEP electrolyte. XPS depth profile analysis shows that the improved cycling stability of the composite is closely related to the reversible dynamic evolutions and conversions of the sulfurcontaining species in the solid electrolyte interphase (SEI) during the charge/ discharge process. This dynamic reversible SEI concept may provide a new strategy for the design of superior electrodes for PIBs.

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Enhanced Potassium Storage Performance for K-Te Batteries via Electrode Design and Electrolyte Salt Chemistry

Cited by 20 publications

References 61 publications

Polyacrylonitrile‐Reinforced Composite Gel Polymer Electrolytes for Stable Potassium Metal Anodes

Polyacrylonitrile‐Reinforced Composite Gel Polymer Electrolytes for Stable Potassium Metal Anodes

High‐Performance Potassium‐Tellurium Batteries Stabilized by Interface Engineering

Dynamic Reversible Evolution of Solid Electrolyte Interface in Nonflammable Triethyl Phosphate Electrolyte Enabling Safe and Stable Potassium‐Ion Batteries

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