Unraveling the fundamentals of Li-O(2) battery chemistry is crucial to develop practical cells with energy densities that could approach their high theoretical values. We report here a straightforward chemical approach that probes the outcome of the superoxide O(2)(-), thought to initiate the electrochemical processes in the cell. We show that this serves as a good measure of electrolyte and binder stability. Superoxide readily dehydrofluorinates polyvinylidene to give byproducts that react with catalysts to produce LiOH. The Li(2)O(2) product morphology is a function of these factors and can affect Li-O(2) cell performance. This methodology is widely applicable as a probe of other potential cell components.

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The possibility of achieving high-energy, long-life storage batteries has tremendous scientific and technological significance. A prime example is the Li–S cell, which can offer a 3–5-fold increase in energy density compared with conventional Li-ion cells, at lower cost. Despite significant recent advances, there are challenges to its wide-scale implementation. Upon sulfur reduction, intermediate soluble lithium polysulfides readily diffuse into the electrolyte, causing capacity fading and poor Coulombic efficiency in the cell. Herein, we increase the capacity retention and cycle life of the Li–S cell through the use of nanocrystalline and mesoporous titania additives as polysulfide reservoirs and examine the role of surface adsorption vs pore absorption. We find that the soluble lithium polysulfides are preferentially absorbed within the pores of the nanoporous titania at intermediate discharge/charge. This provides the major factor in stabilizing capacity although surface binding (adsorption) also plays a more minor role. A cell containing TiO2 with a 5 nm pore diameter exhibited a 37% greater discharge capacity retention after 100 cycles than a cell without the titania additive, which was optimum compared to the other titania that were examined.

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Überlegenes Kathodenmaterial: Sphärische geordnete mesoporöse Kohlenstoffnanopartikel mit sehr hoher Porosität (Porenvolumen von 2.32 cm3 g−1 bei einer Oberfläche von 2445 m2 g−1) wurden in einem zweistufigen Abgussprozess hergestellt. Die Nanopartikel wurden als Kathodenmaterial in Li‐S‐Batterien eingesetzt, wo sie hohe reversible Kapazitäten von bis zu 1200 mA h g−1 bei exzellenter Zyklenstabilität zeigten.