1. Diffusion of Zirconium (IV) Ions from Coated Thick Zirconium Oxide Shell to the Bulk Structure of Ni-rich NMC811 Cathode Leading to High-performance 18650 Cylindrical Li-ion Batteries
Suchakree Tubtimkuna, Nutthaphon Phattharasupakun, Panyawee Bunyanidhi, Montree Sawangphruk
2.. Regulating the Cationic Rearrangement of Ni-rich Layered Oxide Cathode for High-performance Li-ion Batteries
Selvamani Vadivel, Krisara Srimanon, Montree Sawangphruk
Journal of Power Sources, 2022, 537, 231526
Abstract: Enormous effort has been paid to improve Ni-rich cathode's performance by suppressing surface residues and enhancing microscopic surface ordering (high Ni3+/Ni2+). Herein, strong alkali-mediated chemical oxidation of commercial precursor is employed to directly synthesize Ni-rich NCA cathode sintering under an oxygen atmosphere. Because of the limited lithium source, the lithium residue over the polycrystalline material is controlled; of course, a certain fraction of lithium has been lost and substituted by Ni2+, even pre-oxidized the precursor. XPS studies suggest that the percentage of oxidized nickel (Ni3+) is comparably higher at the surface than core (∼100 nm in depth) and retained during the lithiation. The synthesized material initially shows a high reversible lithiation efficiency of 90.6% at 0.05 C. The capacity degradation in the life-cycle study at 0.2 C could be endorsed to the combination of lithium inventory and active metal loss along with typical kinetic limitations, as diagnosed from the derivative dQ/dV plot. The high initial coulombic efficiency and discharge capacity with low polarization further confirm superior surface ordering and low surface residue. This study demonstrates that the pretreatment of the precursor is one of the effective strategies to regulate the cationic arrangement to achieve improved electrochemical performance.
3. Core-shell structure of LiMn2O4 cathode material reduces phase transition and Mn dissolution in Li-ion batteries
Chanikarn Tomon, Sangchai Sarawutanukul, Nutthaphon Phattharasupakun, Salatan Duangdangchote, Praeploy Chomkhuntod, Nattanon Joraleechanchai, Panyawee Bunyanidhi, Montree Sawangphruk
Communications Chemistry, 2022, 5 , 54
Abstract: Although the LiMn2O4 cathode can provide high nominal cell voltage, high thermal stability, low toxicity, and good safety in Li-ion batteries, it still suffers from capacity fading caused by the combination of structural transformation and transition metal dissolution. Herein, a carbon-coated LiMn2O4 cathode with core@shell structure (LMO@C) was therefore produced using a mechanofusion method. The LMO@C exhibits higher cycling stability as compared to the pristine LiMn2O4 (P-LMO) due to its high conductivity reducing impedance growth and phase transition. The carbon shell can reduce direct contact between the electrolyte and the cathode reducing side reactions and Mn dissolution. Thus, the cylindrical cell of LMO@C//graphite provides higher capacity retention after 900 cycles at 1 C. The amount of dissoluted Mn for the LMO@C is almost 2 times lower than that of the P-LMO after 200 cycles. Moreover, the LMO@C shows smaller change in lattice parameter or phase transition than P-LMO, indicating to the suppression of λ-MnO2 phase from the mixed phase of Li1-δMn2O4 + λ-MnO2 when Li-delithiation at highly charged state leading to an improved cycling reversibility. This work provides both fundamental understanding and manufacturing scale demonstration for practical 18650 Li-ion batteries.
4. The charge density of intercalants inside layered birnessite manganese oxide nanosheets determining Zn-ion storage capability towards rechargeable Zn-ion batteries
Praeploy Chomkhuntod, Kanit Hantanasirisakul, Salatan Duangdangchote, Nutthaphon Phattharasupakuna, Montree Sawangphruk
Journal of Materials Chemistry A, 2022, 10, 5561-5568
Abstract: Rechargeable aqueous Zn–MnO2 batteries have been considered as one of the promising alternative energy technologies due to their high abundance, environmental friendliness, and safety of both Zn–metal anodes and manganese oxide cathodes. Although layer-type MnO2 (δ-MnO2) is one of the most promising intercalation cathode materials, there are some critical drawbacks such as sluggish Zn2+ diffusion kinetics and a phase transition of δ-MnO2 as a result of a strong electrostatic interaction between Zn2+ and the host structure. Herein, we systematically studied the effects of the charge density of pre-intercalated cations in layered MnO2 using Li+, Ca2+, and Al3+ on its structural properties and electrochemical performance as a cathode in aqueous Zn–MnO2 batteries. The results reveal that a small amount of highly charged intercalant can effectively stabilize the MnO2 layers, facilitating the kinetics of Zn2+ intercalation/deintercalation. As a result, Al–MnO2 exhibits superior capacity and a rate capability of 210 mA h g−1 with 21% capacity retention when the current density is increased from 0.1 to 2 A g−1, while Ca–MnO2 and Li–MnO2 exhibit 189 and 160 mA h g−1 with a capacity retention of 17% and 11%, respectively. The superior capacity of Al–MnO2 is attributed to the enhanced redox activity from more Mn electrochemical utilization as confirmed by ex situ X-ray photoelectron spectroscopy. Moreover, the long-term cycling stability evaluated at 2 A g−1 shows that Al–MnO2 exhibits superior cycling stability with 84% capacity retention over 2000 cycles. As revealed by ex situ X-ray diffraction and theoretical calculations, the highly charged intercalant can minimize the binding energy between Zn2+ and the MnO2 host, alleviating the strong electrostatic attraction that can induce reversible Zn2+ insertion/extraction.
5. Enzyme-immobilized 3D silver nanoparticle/graphene aerogel composites towards biosensors
Wongduan Sroysee, Ketsuda Kongsawatvoragul, Phitchayapha Phattharaphuti, Pattranit Kullawattanapokin, Chonticha Jangsan, Worapol Tejangkura, Montree Sawangphruk
Materials Chemistry and Physics, 2022, 277, 125572
Abstract: The detection of allergen sulfite is essential for food quality control and public health supervision. Here, a high-performance sulfite biosensor was developed from a sulfite oxidase enzyme (SOx) immobilized on silver nanoparticles (AgNPs) decorated on 3D reduced graphene oxide (3D-rGO). 3D-rGO with high specific pore volume and high electroactive surface area is ideal as a supporting material. AgNPs further provide high electrical conductivity or fast charge transfer and serve as an enzyme anchoring site via a stable thiol bonding. The composite material was initially functionalized with the folic acid and cysteine namely rGO@Ag-Cys-FA before immobilized with the SOx. The resultant rGO@Ag-Cys-FA-SOx exhibits high sensitivity and selectivity towards sulfite detection, high bio-electrocatalytic activity, and fast heterogeneous electron transfer rate constant. The biosensor is also tested in a continuous flow injection system to demonstrate the practical use. Besides, the as-produced sensor in this work can be used in the real sample, which is the canned fruit product indicating its potential practical application.
6. Free carbonate-based molecules in the electrolyte leading to severe safety concern of Ni-rich Li-ion batteries
Nattanon Joraleechanchai, Ruttiyakorn Donthongkwa, Salatan Duangdangchote, Nutthaphon Phattharasupakun, Poramane Chiochan, Kan Homlamai and Montree Sawangphruk
Chemical Communications, 2022, 58, 779-782
Abstract: The safety of Li-ion batteries is one of the most important factors, if not the most, determining their practical applications. We have found that free carbonate-based solvent molecules in the hybrid electrolyte system can cause a severe safety concern. Mixing ionic liquids to the carbonate-based solvent as the co-solvent at fixed 1M LiPF6 salt can lead to free carbonate-based molecules causing poor charge storage performance and safety concerns.