Unlock Restricted Capacity via OCe Hybridization for LiOxygen Batteries

The aprotic Li-O₂ battery (LOB) has the highest theoretical energy density of any rechargeable batteries. However, such system is largely restricted by the electrochemically formed lithium peroxide (Li₂ O₂ ) on the cathode surface, leading ultimately to low actual capacities and early cell death. In contrast to the surface-mediated growth of thin film with a thickness <50 nm, a non-crystalline Li₂ O₂ film with a thickness of >400 nm can be formed via an optimal OCe hybridized electronic structure. Specially, oxygen can react with dissolved cerium cations in the electrolyte via a cerium-oxygen reaction to form a high-energy faceted cerium oxide catalyst, which not only generates a great number of non-saturable active sites, but also erects electron transport bridges between the lattice O and adjacent Ce atoms. Such CeO orbital hybridization also forms a direct charge transfer channel from Ce-4f of CeO₂ to O 2 2 - ${\rm{O}}_2^{2 - }$ -π* of Li₂ O₂ , eventually leading to submicron-thick Li₂ O₂ shells via a subsequent lithium-oxygen reaction. Relying on the above merits, this work unlocks the rechargeable capacities of LOB from restricted 1000 to unprecedented 10 000 mAh g^-1 with good cyclabilities and reduced charge-discharge overpotentials.

Calcium Carbonate Nanoplate Assemblies with Directed High-Energy Facets: Additive-Free Synthesis, High Drug Loading, and Sustainable Releasing

Developing drug delivery systems (DDSs) with high drug-loading capacity and sustainable releasing is critical for long-term chemotherapeutic efficacy, and it still remains challenging. Herein, vaterite CaCO3 nanoplate assemblies with exposed high-energy {001} facets have been synthesized via a novel, additive-free strategy. The product shows a high doxorubicin-loading capacity (65%); the best of all the CaCO3-based DDSs so far. Also, the product's sustainable releasing performance and its inhibition of the initial burst release, together, endow it with long-term drug efficacy. The work may shed light on exposing directed high-energy facets for rationally designing of a drug delivery system with long-term efficacy.