Anode-free sodium batteries (AFSBs) offer a promising route to low cost, high-energy-density energy storage, but their practical application is limited by irreversible sodium loss during cycling. Here we report a molecular-level electrolyte design strategy that mitigates sodium loss by simultaneously promoting highly reversible sodium deposition and suppressing electrolyte decomposition, enabled by the cyclic ether 1,3-dioxane (DOX). Weak coordination of DOX with Na+ facilitates Na+ desolvation and reversible sodium deposition, while controlled DOX oligomerization forms a thin and robust solid–electrolyte interphase that suppresses continuous electrolyte decomposition and stabilizes sodium plating/stripping. As a result, 300-mAh-level AFSB pouch cells with a cathode loading of ~20 mg cm−2 retain ~80% capacity after 1,400 cycles at 1 C, operate at rates up to 3 C, maintain 88% capacity at −40 °C and achieve a round-trip energy efficiency up to ~98%. These results demonstrate a molecular electrolyte design strategy for extending the lifetime of AFSBs. Anode-free sodium batteries are limited by irreversible sodium loss during cycling. Here the authors introduce a moderate-strain cyclic ether that redirects electrolyte decomposition to form a thin, robust interphase, thereby minimizing sodium consumption and extending cycling stability.
Formamidinium (FA)-doped caesium lead triiodide, Cs(FA)PbI3, is a promising front-cell absorber for tandem solar cells owing to its good stability, yet obtaining high-quality films remains a challenge. Here we identify that sparse doping of oversized FA cations induces severe grain boundary (GB) distortion, thereby facilitating defect generation and performance deterioration. To mitigate this, we develop a Pb-based metallomesogen that forms a mesophase exhibiting both solid-like and liquid-like properties. The phase characteristics enable the Pb-based metallomesogen to distribute uniformly along GBs of Cs(FA)PbI3 film, alleviating GB distortion, relieving shear strain, preserving lattice integrity and mitigating defect formation. Consequently, perovskite/silicon tandem solar cells based on a 1.66-eV Cs(FA)PbI3 absorber incorporating a Br-containing GB modifier achieve a champion efficiency of 32.08% (certified 31.62%), retaining 95% of the initial performance after ~3,000 h under maximum power point tracking and 93% after 1,500 h under 85% relative humidity and 85 °C damp-heat stressing. Formamidinium–caesium lead triiodide perovskites show promise in terms of stability, yet their solar cell efficiency remains limited. Li et al. use a metallomesogen with mesophase to stabilize perovskite grain boundaries, improving both the efficiency and stability of perovskite/silicon tandem solar cells.
Anode-free sodium batteries eliminate excessive sodium on the anode, maximizing cell-level energy density, but are limited by irreversible sodium loss during electroplating–stripping. Now, a low-strain cyclic solvent forms an oligomerized interphase, enabling highly reversible sodium deposition without functional additives or electrode modifications.
Electric power systems are evolving into cyber–physical infrastructures shaped by power electronics and digital control. As inverter-based generation alters system dynamics and digitalization heightens vulnerability to errors and attacks, cyber–physical coupling can also introduce subtle system-level effects. Here we show that grid-frequency time series worldwide exhibit a persistent 1-min oscillatory pattern whose origin has remained unexplained. We show that clock-synchronized control software in digitally controlled energy devices, particularly uninterruptible power supplies and battery energy storage systems, generates periodic power-demand peaks that propagate across voltage levels and can give rise to the observed pattern. The pattern amplitude has increased substantially in several grids over recent years, contributing to wear and tear in hydropower systems and motivating stricter frequency-control requirements. The rapid expansion of battery storage, data centres and the Internet-of-Things may further amplify such cyber–physical power oscillations, highlighting the need for improved control design. Power grids on five continents show frequency oscillations with a period of exactly 1 min. The authors trace this to clock-synchronized software in devices such as uninterruptible power supplies that creates coherent, repeating demand peaks.
