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Lithium-sulfur (Li-S) batteries have been considered as promising battery systems due to their huge advantages on theoretical energy density and rich resources. However, the shuttle effect and sluggish transformation of soluble lithium polysulfides (LiPSs) hinder the practical application of Li-S batteries.Tremendous sulfur host materials with unique catalytic activity have been exploited to inhibit the shuttle effect and accelerate LiPSs redox reactions, in which theoretical simulations have been widely adopted. This review aims to summarize the fundamentals and applications of theoretical models in sulfur cathodes. Concretely, the integration of theoretical models provides insights into the adsorption and conversion mechanisms of LiPSs and is further utilized in the smart design of catalysts for the exploitation of practical Li-S batteries. Finally, a perspective on the future combination of calculation technology and theoretical models is provided.

The outbreak of the COVID-19 pandemic is partially due to the challenge of identifying asymptomatic and pre-symptomatic carriers of the virus, and thus highlights a strong motivation for diagnostics that can be rapidly deployed with high sensitivity. On the other hand, several concerned SARS-CoV-2 variants, including the Omicron, are required to be identified as soon as the samples are identified as ‘positive’. Unfortunately, a traditional PCR test does not allow their specific identification. Herein, for the first time, we have developed MOPCS (Methodologies of Photonic CRISPR Sensing), which combines an optical sensing technology-surface plasmon resonance (SPR), and the ‘gene scissors’ CRISPR technique to achieve both high sensitivity and specificity of viral variants’ measurement. MOPCS is a low-cost, CRISPR/Cas12a system-empowered SPR gene detecting platform that can analyze viral RNA, without the need for amplification, within 38 min from sample input to results output, and achieve a limit of detection of 15 fM. MOPCS achieves a highly sensitive analysis of SARS-CoV-2 and mutations appear in variants B.1.617.2 (Delta), B.1.1.529 (Omicron), and BA.1 (a subtype of Omicron). This platform was also used to analyze some recently collected patient samples from a local outbreak in China and identified by the Centers for Disease Control and Prevention. This innovative CRISPR-empowered SPR platform will further contribute to various fast, sensitive, and accurate detection of target nucleic acid sequences with single-base mutations.

Organic-inorganic methylammonium lead halide perovskites have recently attracted great interest emerging as promising photovoltaic materials with a high 20.8% efficiency, but lead pollution is still a problem that may hinder the development and wide spread of MAPbI3 perovskites. To reduce the use of lead, we investigated the structures, electronic and optical properties of mixed MAGexPb(1-x)I3 theoretically by using density functional theory methods at different calculation levels. Results show that the mixed Ge/Pb perovskites exhibit a monotonic decrease evolution in band energy to push the band gap deeper in the near-infrared region and have a red shift optical absorption with an increased proportion of Ge. The results also indicate that lattice distortion and spin-orbit coupling (SOC) strength play important roles in the band gap behavior of MAGexPb(1-x)I3 by affecting the bandwidths of CBM and VBM. The calculations for short circuit current density, open circuit voltage, and theoretical power conversion efficiency suggest that mixed Ge/Pb perovskite solar cells (PSCs) with efficiency over 22% are superior to MAPbI3 and MAGeI3. And notably, MAGe0.75Pb0.25I3 is a promising harmless material for solar cells absorber with the highest theoretical efficiency of 24.24%. These findings are expected to be helpful for further rational design of nontoxic light absorption layer for high-performance PSCs.