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The demand for rechargeable batteries with high gravimetric and volumetric energy density will continue to grow due to the rapidly increasing integration of renewable energy into the global energy scheme. In terms of energy density, modern high-end rechargeablebattery technology is reaching its fundamental limits and no big advancement leaps in this field are expected. The energy-cost model, developed for comparative evaluation of battery cell chemistries in a commercial type pouch cell configuration, helps us to find the relationship between cost and energy density, enabling the prediction of the most promising material combinations for near-future non-aqueous rechargeable batteries for portable electronics and automotive applications. Among the wide variety of positive electrode materials only few show enough potential for commercialization, and, clearly, the immediate future will still be dominated by Li-ion technology, with Li-rich and Ni-rich materials as definite winners, and with Li-S and Na-ion emerging as contestants due to low cost and abundance of their key components. As further significant improvements in gravimetric/volumetric energy density and cost cannot be achieved through new battery chemistries, then the engineering, targeting cost reduction and safety assurance, will most likely be the main driving force behind future rechargeable battery development.One of the most important roles of research and development today is to steer technology toward long-term sustainability for generation, storage, and consumption of energy. Handling global warming, pollution, and energy shortage is a serious challenge, and failure to address it timely will have severe environmental and political consequences. Only a widespread integration of renewable energy generation, supported by efficient energy storage, can provide a long-term solution. Fortunately, renewables have already begun to affect several major societal energy sectors, such as transportation and electrical grids, albeit so far to a very moderate extent due to inefficient and costly energy storage. 1,2 Electrochemical energy storage provides the most efficient, clean, and feasible solution for high-end applications, as illustrated by the successful battery integration into long drive-range electric vehicles (EV). Because of the immense interest in electrochemical energy storage from both government funding agencies and industry in recent years, activities in this field have surged. This makes the continuous critical reassessment of new battery chemistries and concepts based on the latest state of research valuable.Here we assess active materials designated for high-performance non-aqueous rechargeable batteries for portable electronics and automotive applications according to their commercialization potential within the coming decade. Non-aqueous electrolytes generally offer higher energy densities due to their wider electrochemical stability window, enabling a higher cell voltage (>2 V). In this respect, Liion is the superior battery technology, outp...

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Lithium-rich mixed metal layered oxides constitute a large class of promising high-potential positive electrode materials in which higher specific charges are accessed only by activation of the Li2MnO3 domains. During the activation, oxygen is extracted from the oxide and evolves at the electrode–electrolyte interface. Differential electrochemical mass spectrometry was employed to follow volatile species developed during cycling. Although typical Li-ion aprotic carbonate electrolytes already suffer from oxidative decomposition at high potentials, the presence of O2 is here confirmed to enhance its reactivity. During the first cycle, O2 and CO2 evolve and their respective amounts vary as a function of the cycling conditions. However, for ethylene carbonate-based electrolytes, the amount of O2 and CO2 is found to be independent of the electrolyte composition. Moreover, X-ray photoelectron spectroscopy revealed that carbon-based components of the solid layers are dissolved between 3.0 and 4.0 V versus Li+/Li where no gas is evolving.

Hard carbons (HCs) prepared from renewable precursors are promising cost-effective electrodematerial candidates for the application in Na-ion battery. Usually these materials are derived from cellulose. Here, however, we demonstrate that other polysaccharides, such as chitin and chitosan, can be as well up-and-coming parent materials of HCs. Despite structural similarities, thermal decomposition of these two biopolymers proceeds differently, contributing to the discrepancies in physicochemical properties of resulting HCs. Although chitin-and chitosan-derived HCs have comparable d-spacings and crystallite sizes, solid state pyrolysis of the former biopolymer leads to micro-mesoporous material with significant specific surface area, while that of chitosan yields non-porous carbon. Despite that, both materials deliver similar initial specific charge of 280 mAh g-1 (at C/10 rate) and their electrochemical performance starts to diverge only upon longer cycling at higher rate. With time, inorganic contaminants present in chitosan-derived HC presumably delay the diffusion of Na-ions to and within the electrode, and slow down the rate of electrochemical reactions, eventually triggering polarization build-up. Further optimization of the chitosan-derived HC through acid-treatment enables unblocking some of the micropores and increasing the carbon content in this material, therefore enhancing its active surface area and suppressing continuous fading of the specific charge.