Kinnor Chattopadhyay

Lithium–sulphur (Li–S) batteries suffer from capacity loss due to the dissolution of lithium polysulfides (LiPSs). Although finding cathodes that can trap LiPSs strongly is a possible solution to suppress the “shuttle” effect, fast diffusion of lithium and LiPSs is also pivotal to prevent agglomeration. We report that monolayer blue phosphorene (BP), a recently synthesized two-dimensional material, possesses these characteristics as a cathode in Li–S batteries. Density functional theory… Show more

Lithium–sulphur (Li–S) batteries suffer from capacity loss due to the dissolution of lithium polysulfides (LiPSs). Although finding cathodes that can trap LiPSs strongly is a possible solution to suppress the “shuttle” effect, fast diffusion of lithium and LiPSs is also pivotal to prevent agglomeration. We report that monolayer blue phosphorene (BP), a recently synthesized two-dimensional material, possesses these characteristics as a cathode in Li–S batteries. Density functional theory calculations showed that while the adsorption energies (Eb) of various LiPSs over pristine BP are reasonably strong (from −0.86 eV to −2.45 eV), defect engineering of the lattice by introducing a single vacancy (SV) increased the binding strength significantly, with Eb in the range of −1.41 eV to −4.34 eV. Ab-initio molecular dynamics simulations carried out at 300 K showed that the single vacancies trap the Li atoms in the LiPSs compared to pristine BP. Projected density of states revealed that the creation of an SV induces metallicity in the cathode. Furthermore, an increase in the adsorption strength did not cause significant structural deformation, implying that the soluble large LiPSs did not decompose, which is essential to suppress capacity fading. The energy barriers for LiPSs’ migration over pristine BP are minimal to ensure ultrafast diffusion, with the lowest diffusion energy barriers being 0.23 eV, 0.13 eV and 0.18 eV for Li2S4, Li2S6 and Li2S8, respectively. Furthermore, the energy barrier associated with the catalytic oxidation of Li2S over pristine and defective BP was found to be greater than three times smaller compared to graphene, which suggests that charging processes could be faster by orders of magnitude. Therefore, BP with a suitable combination of defects would be an excellent cathode material in Li–S batteries. Show less

Battery manufacturers are driven by the need to produce batteries with high energy densities and faster charging. For batteries to deliver such demands one would require a combination of high-performance anode materials with next-generation liquid electrolytes. Anodes made of graphene hold immense promise for revolutionizing next-generation rechargeable Li/Na ion batteries. Although experiments have demonstrated the capability of graphene anodes, vacuum-based density functional theory (DFT)… Show more

Battery manufacturers are driven by the need to produce batteries with high energy densities and faster charging. For batteries to deliver such demands one would require a combination of high-performance anode materials with next-generation liquid electrolytes. Anodes made of graphene hold immense promise for revolutionizing next-generation rechargeable Li/Na ion batteries. Although experiments have demonstrated the capability of graphene anodes, vacuum-based density functional theory (DFT) calculations predict pure graphene to perform poorly owing to limited intercalation and unsatisfactory diffusivity of Li/Na. In a battery, depending on the polarizability of the medium, the interactions between electrodes and metal atoms can vary which may affect performance. Herein, the effect the permittivity of liquid electrolytes on the performance of graphene-based Li/Na ion batteries was studied using implicit solvation DFT calculations. Binding energy between graphene and adatoms was found to monotonically increase with εr, even going from positive to negative, indicative of an energetically favorable intercalation and improved storage. Also, with εr ≥ 11.5, diffusion of Li (Na) was found to increase dramatically by over 106 (2 × 102) times relative to vacuum. These results provide insights into the operation of graphene-based ion batteries and provide guidelines for their design. Show less

https://scholar.google.ca/citations?user=WvNXdrMAAAAJ&hl=en

Lithium-ion batteries (LIBs) have attracted increasing attention for electrical energy storage applications in recent years due to their excellent electrochemical performance. The unprecedented growth trajectory in lithium-ion battery manufacturing perpetuated by the inception of electric vehicles (EV) results in a vast amount of spent LIBs reaching their end of life (EOL). From the perspective of resource circulation, procurement, and sustainability with an insight into the circular economy… Show more

Lithium-ion batteries (LIBs) have attracted increasing attention for electrical energy storage applications in recent years due to their excellent electrochemical performance. The unprecedented growth trajectory in lithium-ion battery manufacturing perpetuated by the inception of electric vehicles (EV) results in a vast amount of spent LIBs reaching their end of life (EOL). From the perspective of resource circulation, procurement, and sustainability with an insight into the circular economy, an effective recycling system must be developed to recycle the spent LIBs. This paper provides a comprehensive overview of the current status of pyrometallurgical options for recycling spent LIBs. In particular, this study summarizes the thermal pretreatment methods used to recover the active cathode material and then discusses the developed extractive pyrometallurgical options for recycling spent LIBs. A summary is presented on some recent examples of laboratory and industrial-scale recycling processes to demonstrate the practical applications of pyrometallurgical options for recycling. Finally, the review sheds light on the battery recycling legislation, and challenges and future outlook for recycling LIBs are also discussed. Show less

The rapid growth in silicon photovoltaics deployment has led to increased research focus on the energy and capital intensive refining of solar grade silicon for improved environmental, production and economic benefits. As this process consists of a number of steps taking place in multi-phase reacting systems with complex fluid and energy flows, models can be an important tool for mechanistic understanding, design and optimization. This paper reviews models for the most widely implemented… Show more

The rapid growth in silicon photovoltaics deployment has led to increased research focus on the energy and capital intensive refining of solar grade silicon for improved environmental, production and economic benefits. As this process consists of a number of steps taking place in multi-phase reacting systems with complex fluid and energy flows, models can be an important tool for mechanistic understanding, design and optimization. This paper reviews models for the most widely implemented refining techniques and classifies them into two broad categories; those relating to the synthesis of volatile Si based compounds and those relating to the deposition of volatile silicon based compounds. Within each category, models are further divided according to the reactor type or physical process which they are examining. These models typically use computational techniques with various combinations of theory for obtaining chemical thermodynamics, chemical kinetics, fluid mechanics and heat and mass transfer information for a system. The system definition, main assumptions, computational techniques and main results for each study are presented. There is also a brief review of ab initio atomistic studies for this area along with a discussion for future research. This work should help researchers in selecting appropriate physical and chemical models for investigating solar grade silicon refining or further developing their own models. Show less

Replacing coke (coal) in a metallurgical furnace with other alternative fuels is beneficial for process economics and environmental friendliness. Coal injection is a common practice in blast furnace ironmaking, and spent pot-lining (SPL) was conceptualized as an alternative to coal. SPL is a resourceful waste from primary Aluminum production, with high carbon value. Equilibrium thermodynamics was used to calculate the energy content of SPL, and the compositional changes during SPL combustion… Show more

Replacing coke (coal) in a metallurgical furnace with other alternative fuels is beneficial for process economics and environmental friendliness. Coal injection is a common practice in blast furnace ironmaking, and spent pot-lining (SPL) was conceptualized as an alternative to coal. SPL is a resourceful waste from primary Aluminum production, with high carbon value. Equilibrium thermodynamics was used to calculate the energy content of SPL, and the compositional changes during SPL combustion. In order to capture the kinetics and mass transfer aspects, a blast furnace tuyere region CFD model was developed. The results of SPL combustion were compared with standard PCI coals, which are commonly used in blast furnaces. The CFD model was validated with experimental results for standard high volatile coals. Show less