The evolution of energy storage technology that can deliver high energy density with excellent rate performance is desirable all around. The scientific community putting their efforts together to solve this...

Phosphate-based Cathode Materials to boost the electrochemical performance of Sodium-ion Battery

The essential requirement to harness well-known renewable energy sources like wind energy, solar energy, etc. as a component of an overall plan to guarantee global power sustainability will require highly efficient, high power and energy density batteries to collect the derived electrical power and balance out variations in both supply and demand. Owing to the continuous exhaustion of fossil fuels, and ever increasing ecological problems associated with global warming, there is a critical requirement for searching for an alternative energy storage technology for a better and sustainable future. Electrochemical energy storage technology could be a solution for a sustainable source of clean energy. Sodium-ion battery (SIB) technology having a complementary energy storage mechanism to the lithium-ion battery (LIB) has been attracting significant attention from the scientific community due to its abundant resources, low cost, and high energy densities. Layered transition metal oxide (TMO) based materials for SIBs could be a potential candidate for SIBs among all other cathode materials. In this paper, we discussed the latest improvement in the various structures of the layered oxide materials for SIBs. Moreover, their synthesis, overall electrochemical performance, and several challenges associated with SIBs are comprehensively discussed with a stance on future possibilities. Many articles discussed the improvement of cathode materials for SIBs, and most of them have pondered the use of NaxMO2 (a class of TMOs) as a possible positive electrode material for SIBs. The different phases of layered TMOs (NaxMO2; TM = Co, Mn, Ti, Ni, Fe, Cr, Al, V, and a combination of multiple elements) show good cycling capacity, structural stability, and Na+ ion conductivity, which make them promising cathode material for SIBs. This review discusses and summarizes the electrochemical redox reaction, structural transformations, significant challenges, and future prospects to improve for NaxMO2. Moreover, this review highlights the recent advancement of several layered TMO cathode materials for SIBs. It is expected that this review will encourage further development of layered TMOs for SIBs.

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Transition metal oxides as a cathode for indispensable Na-ion batteries

Fast ionic conduction and rectification effect of NaCo0.5Fe0.5O2-CeO2 nanoscale heterostructure for LT-SOFC electrolyte application

The initial process of Li-metal electrodeposition on the negative electrode surface determines the charging performance of Li-metal secondary batteries. However, minute depositions or the early processes of nucleation and growth of Li metal are generally difficult to detect under operando conditions. In this study, we propose an optical diagnostic approach to address these challenges. Surface plasmon resonance (SPR) spectroscopy coupled with electrochemical operation is a promising technique that enables the ultrasensitive detection of the initial stage of Li-metal electrodeposition. The SPR is excited in a thin copper film deposited on a glass substrate, which also serves as a current collector enabling electrochemical Li-metal deposition. For a propylene carbonate (PC)-based Li-ion battery electrolyte, under both cyclic voltammetry and constant-current operation, Li-metal deposition is readily detected by changes in the SPR absorption dip in the reflectance spectrum. Electrochemical SPR is highly sensitive to metal deposition, with a demonstrated capability of detecting an average thickness of approximately 0.1 nm, corresponding to a few atomic layers of Li. To identify the growth mechanism, the SPR reflectance spectra of various possible Li-metal deposition processes were simulated. Comparison of the simulated spectra with the experimental data found good agreement with the well-known nucleation and growth model for Li-metal deposition from PC-based electrolytes. The demonstrated operando electrochemical SPR measurement should be a valuable tool for basic research on the initial Li-metal deposition process.

Electrochemical Surface Plasmon Resonance Spectroscopy for Investigation of the Initial Process of Lithium Metal Deposition.

Tantalum oxide nanosheets/polypropylene composite separator constructing lithium-ion channels for stable lithium metal batteries

Lithium (Li) metal battery systems are currently gaining significant attention as the most energy-intensive architectures among the various battery architectures being actively examined at present for multiple emergent applications. Although the cathode chemistries in Li metal systems are fairly simple and far less challenging in liquid electrolytes, the metallic chemistry of the anode poses many challenging problems. The dendrite formation and consequent dead Li formation and short circuiting have rendered the practical realization of these promising battery systems extremely hard. Therefore, the issue of dendrite mitigation has recently triggered hectic research efforts by battery scientists around the globe. The major research thrust of this activity has primarily been on gaining deep insights into the dendrite formation using advanced characterization methods. In this review, we seek to understand the Li dendrite formation as an interplay between the solid electrolyte interphase and surface features. We try to understand the dendrite formation as a consequence of the above two parameters via advanced imaging techniques, like X-ray imaging techniques, X-ray computed tomography, atomic force microscopy, and cryo-electron microscopy. Finally, an outlook is presented suggesting the emergent research directions.

Recent Advances in Understanding the Formation and Mitigation of Dendrites in Lithium Metal Batteries

Global interest in the development of sodium-ion batteries (SIBs) continues, largely due to the advantage of the affordable cost of sodium resources (compared to lithium), which could produce cost-effective rechargeable batteries for large-scale applications. However, the discovery of reliable cathodes, tailored amorphous carbon anodes, and compatible electrolytes is required to yield safer, longer lasting SIBs with wide operating temperature. Among various cathodes systems, layered oxide cathodes are of great interest due to 230–245 mAhg−1 theoretical capacity with facile structure forming ability. Among the various phases of NaxCoO2 cathode, the P2 is the most favored, because of low polarization with enhanced structural stability and high theoretical capacity of 183 mAhg−1 for the empirical formula of Na0.74CoO2. Charge/discharge profiles of these systems exhibit plateaus, continuous changes in voltage and voltage drop, which impacts the electrochemical performance. This review discusses recent advancement in NaxCoO2 cathode in terms of the effect of particle morphology, size, crystal structure, electronic structure, cation and anion doping, sacrificial salt, Na deficiency, effect of electrolyte salts and solvents, and thermal safety. We present a comprehensive analysis of the recent developments in NaxCoO2 and its derivative cathode materials and propose various approaches to mitigate the challenges for the near future successful commercialization of SIBs.

Dhanya Puthusseri

Papers

Recent Advances in Understanding the Formation and Mitigation of Dendrites in Lithium Metal Batteries

Layered NaxCoO2-based cathodes for advanced Na-ion batteries: review on challenges and advancements