Synthesis of 3-dimensional interconnected porous Na₃V₂(PO₄)₃@C composite as a high-performance dual electrode for Na-ion batteries

Didwal, Pravin N.,Verma, Rakesh,Min, Chan-Woo,Park, Chan-Jin Elsevier 2019 Journal of Power Sources Vol.413 No.-

<P><B>Abstract</B></P> <P>Three-dimensional (3-D) interconnected porous Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> coated with carbon (NVP@C) is synthesised by a simple modified sol-gel method. When 15 wt% glucose is used as the carbon precursor, the obtained NVP@C15 composite exhibits excellent electrochemical performance as a cathode as well as an anode for sodium-ion batteries (SIBs). As a cathode, the NVP@C15 electrode delivers a high capacity of 116.9 mAh g<SUP>−1</SUP> at a rate of 1 C, which is close to its theoretical capacity. Even at a high rate of 20C, the NVP@C15 electrode exhibits an initial reversible capacity of 99.2 mAh g<SUP>−1</SUP> and a capacity retention of 77% after 6000 cycles. As an anode, the NVP@C15 delivers an initial reversible capacity of 85.8 mAh g<SUP>−1</SUP> at a rate of 1C. At higher rates of 10 and 20C, a remarkably good cyclability, with a capacity retention of 76% over 4000 cycles and 62% over 5000 cycles, respectively, is achieved. Furthermore, the full cell, composed of two symmetric NVP@C15 electrodes, exhibits an initial reversible capacity of 73 mAh g<SUP>−1</SUP> at a rate of 1C. In addition, capacity retentions of 88% after 100 cycles and 61% after 500 cycles are obtained at rates of 1C and 5C, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3-D interconnected porous Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>@C was synthesised by modified sol-gel method. </LI> <LI> 3-D interconnected porous structure provides easy diffusion pathways for Na ions. </LI> <LI> The uniform carbon coating on Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>@C provides better electronic conductivity. </LI> <LI> Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>@C can be used as an anode and a cathode for sodium-ion batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

전고체 전지용 산화물 및 복합 고체 고분자 기반 고체 전해질의 개발 동향

( Pravin N. Didwal ),이귀학,박찬진 대한금속재료학회(구 대한금속학회) 2020 재료마당 Vol.33 No.6

SnP₃/Carbon Nanocomposite as an Anode Material for Potassium-Ion Batteries

Verma, Rakesh,Didwal, Pravin N.,Ki, Hyeong-Seo,Cao, Guozhong,Park, Chan-Jin American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.30

<P>New anode materials with large capacity and long cyclability for next-generation potassium-ion batteries (PIBs) are required. PIBs are in the initial stage of investigation and only a few anode materials have been explored. In this study, for the first time, an SnP<SUB>3</SUB>/C nanocomposite with superior cyclability and rate performance was evaluated as an anode for PIBs. The SnP<SUB>3</SUB>/C nanocomposite was synthesized by a facile and cost-effective high-energy ball-milling technique. The SnP<SUB>3</SUB>/C electrode delivered a first reversible capacity of 410 mAh g<SUP>-1</SUP> and maintained 408 mAh g<SUP>-1</SUP> after 50 cycles at a specific current of 50 mA g<SUP>-1</SUP>. After 80 cycles at a high specific current of 500 mA g<SUP>-1</SUP>, a high capacity of 225 mAh g<SUP>-1</SUP> remained. From a crystallographic analysis, it was suggested that the SnP<SUB>3</SUB>/C nanocomposite underwent a sequential and reversible conversion and alloying reactions. The excellent cycling stability and rate capability of the SnP<SUB>3</SUB>/C electrode were attributed to the nanosized SnP<SUB>3</SUB> particles and carbon buffer layer, which supplied channels for the migration of K-ions and mitigated the stress induced by a large volume change during potassiation/depotassiation. In addition, a full cell composed of the SnP<SUB>3</SUB>/C nanocomposite anode and potassium Prussian blue cathode exhibited a reversible capacity of 305 mAh g<SUP>-1</SUP> at a specific current of 30 mA g<SUP>-1</SUP> and retained 71.7% of the original capacity after 30 cycles. These results are important for understanding the electrochemical process of the SnP<SUB>3</SUB>/C nanocomposite and using the SnP<SUB>3</SUB>/C as an anode for PIBs.</P> [FIG OMISSION]</BR>

Highly efficient and stable solid-state Li-O₂ batteries using a perovskite solid electrolyte

Le, Hang T. T.,Ngo, Duc Tung,Didwal, Pravin N.,Fisher, John G.,Park, Choong-Nyeon,Kim, Il-Doo,Park, Chan-Jin The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.7

<P>The solid-state Li-O2 battery is considered an ideal candidate for high-performance energy storage because of its high safety, due to use of non-flammable and non-volatile electrolytes, and high specific energy, as it uses Li metal and O2 gas as active materials. We present an original solid-state Li-O2 cell composed of a Li metal anode, a flexible polymer interlayer, a perovskite-structured Al-doped Li-La-Ti-O (A-LLTO) solid electrolyte, and an integrated cathode in which a porous A-LLTO solid electrolyte frame was covered with a carbon layer and CoO nanoparticles as the catalyst for the cyclic oxygen evolution and reduction reactions. The designed solid-state cell operated safely in pure O2 atmosphere at temperatures from 25 °C to 100 °C and delivered the first discharge capacity from 796 mA h gC+CoO<SUP>−1</SUP> to 4035 mA h gC+CoO<SUP>−1</SUP>, respectively, at a current density of 0.05 mA cm<SUP>−2</SUP>. Notably, at 50 °C, the cell was maintained for 132 cycles under a limited capacity mode of 500 mA h gC+CoO<SUP>−1</SUP> at a high current density of 0.3 mA cm<SUP>−2</SUP>, demonstrating the first step of success towards realizing Li batteries with high energy and cyclability, as well as safety.</P>

A self-encapsulated porous Sb-C nanocomposite anode with excellent Na-ion storage performance

Pham, Xuan-Manh,Ngo, Duc Tung,Le, Hang T. T.,Didwal, Pravin N.,Verma, Rakesh,Min, Chan-Woo,Park, Choong-Nyeon,Park, Chan-Jin The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.41

<P>In this study, a self-encapsulated Sb-C nanocomposite as an anode material for sodium-ion batteries (SIBs) was successfully synthesised using an SbCl3-citrate complex precursor, followed by a drying and calcination process under an inert N2 atmosphere. When the molar ratio of SbCl3 to citric acid was varied from 1 : 1 to 1 : 4, the Sb-C nanocomposite with a molar ratio of 1 : 3 (Sb-C3) exhibited the highest specific surface area (265.97 m<SUP>2</SUP> g<SUP>−1</SUP>) and pore volume (0.158 cm<SUP>3</SUP> g<SUP>−1</SUP>). Furthermore, the Sb-C3 electrode showed a high reversible capacity of 559 mA h g<SUP>−1</SUP> at a rate of C/10 and maintained a high reversible capacity of 430 mA h g<SUP>−1</SUP> even after 195 cycles at a rate of 1C. The Sb-C3 electrode exhibited an excellent rate capability of 603, 445, and 357 mA h g<SUP>−1</SUP> at the rates of C/20, 5C, and 10C, respectively. Furthermore, a full cell composed of an Sb-C3 anode and a Na3V2(PO4)3 cathode exhibited good specific capacity and cyclability, making the Sb-C composite a promising anode material for high-performance SIBs.</P>

Atomic layer deposited zinc oxysulfide anodes in Li-ion batteries: an efficient solution for electrochemical instability and low conductivity

Sinha, Soumyadeep,Ramasamy, Hari Vignesh,Nandi, Dip K.,Didwal, Pravin N.,Cho, Jae Yu,Park, Chan-Jin,Lee, Yun-Sung,Kim, Soo-Hyun,Heo, Jaeyeong The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.34

<P>In addition to their optoelectronic applications, Zn-based oxides and sulfides have also been widely studied as electrode materials in Li-ion batteries owing to their high theoretical capacity. However, both the materials suffer from a drastic loss in capacity due to their poor conductivity and electrochemical instability. A very efficient and carefully controlled combination of these two may address these limitations. In this work, thin films of zinc oxysulfide (ZnOS) with an O/(O + S) ratio of ∼0.7 were deposited using a combination of oxide and sulfide atomic layer deposition (ALD) cycles; they were then tested as anodes in Li-ion batteries. The material was grown directly on a stainless steel substrate (SS), characterized extensively using several <I>ex situ</I> characterization tools, and then used as an anode with no binder or conductive additives. Cyclic voltammetry measurements were used to confirm the reversible conversion of ZnOS in addition to the well-known alloying-dealloying Li-Zn reaction. The material loading was further optimized by varying the number of ALD supercycles to attain the maximum stable cycling performance. The highest stable capacities of 632.9 and 510.3 mA h g<SUP>−1</SUP> were achieved at current densities of 0.1 and 1 A g<SUP>−1</SUP> (∼4 and 40 μA cm<SUP>−2</SUP>), respectively, for a ZnOS film with an optimum thickness of ∼75 nm. The optimized ZnOS anode exhibited superior electrochemical performance in comparison to the equivalent pristine ZnO and ZnS anodes. Finally, the post-cycling analysis of the binder-free ALD grown ZnOS anodes demonstrated excellent adhesion to the SS substrate and the high stability of these films upon cycling.</P>