Fuel cells could play an important role in the ongoing energy transition by providing clean and efficient energy conversion. Although the solid oxide fuel cell (SOFC) technology is a potential alternative for large-scale applications, its commercialization is limited by its electrolyte materials and has not yet been realized. Progress on new functional semiconductor-ionic materials (SIMs) and the fundamentals of SOFCs will provide new paths for their research and development. Herein, we discuss the nanoscale electrochemistry phenomena of SIMs in the context of new concepts for advanced SOFCs. A traditional SOFC consists of a three-layer anode/electrolyte/cathode structure, where the physically separated electrolyte layer is indispensable for ion transport to support the redox reaction and prevent the occurrence of short circuiting. A novel nano-SOFC concept is proposed to replace the traditional electrolyte by a SIM or semiconductor membrane and it can deliver superior performance, even at a lower temperature range (< 500 °C). The scientific basis and prospects of this new technological approach are presented and discussed.

The rapid expansion of electric vehicles and mobile electronic devices is the main driver for the improvement of advanced high-performance lithium-ion batteries (LIBs). The electrochemical performance of LIBs depends on the specific capacity, rate performance and cycle stability of the electrode materials. In terms of the enhancement of LIB performance, the improvement of the anode material is significant compared with the cathode material. There are still some challenges in producing an industrial anode material that is superior to commercial graphite. Based on the different electrochemical reaction mechanisms of anode materials for LIBs during charge and discharge, the advantages/disadvantages and electrochemical reaction mechanisms of intercalation-, conversion- and alloying-type anode materials are summarized in detail here. The methods and strategies for improving the electrochemical performance of different types of anode materials are described in detail. Finally, challenges for the future development of LIBs are also considered. This review offers a meaningful reference for the construction and performance optimization of anode materials for LIBs.

Rechargeable batteries with high capacity, power and safety are urgently required for current and future technological demands. The solid electrolyte interphase (SEI) layer has a dominant impact on battery cyclability and the solvate is the key factor that determines the SEI layer. In this perspective, we first review the recent advances in understanding the influences of electrolyte composition on the solvation chemistry and SEI layer. The solvation structure of electrolytes seems to be the root cause of the stability of electrodes during cell cycling. We then discuss the strategy to manipulate the solvation chemistry by adjusting the compositions of the electrolytes, including the solvent, salt, concentration and additive. Finally, we concisely discuss the challenges in characterizing the structure of the solvates at the electrode|electrolyte interface. This review refreshes our current understanding of the key factors for stable electrode|electrolyte interfaces in the pursuit of high-performance battery systems.

A highly fluorinated additive, pentafluoropyridine (PFP), is used here to enhance the interfacial stability of the Ni-rich LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90) cathode at a cut-off voltage of 4.3 V vs. Li/Li⁺ at 30 °C. The capacity retention of the NCM90||Li cell is obviously improved from 72.3% to 80.3% after 200 cycles at 1C (1C = 180 mA g^-1) when 0.2% PFP is introduced into the baseline electrolyte (1 mol L^-1 LiPF₆ in ethylene carbonate/diethyl carbonate). The improvement in electrochemical performance could be attributed to the formation of a compact and uniform cathode electrolyte interphase (CEI) layer enriched with F-containing polypyridine moieties and LiF species on the NCM90 particles. This CEI prevents side reactions between the electrode and electrolyte and hinders the corrosion of the cathode caused by HF attack. In addition, the formation of internal particle cracks is somewhat suppressed by the robust CEI, thus prohibiting the irreversible phase transformation and better maintaining the superior lithium-ion diffusion kinetics.

Perovskite materials are central to the fields of energy conversion and storage, especially for fuel cells. However, they are challenged by overcomplexity, coupled with a strong desire for new materials discovery at high speed and high precision. Herein, we propose a new approach involving a combination of extreme feature engineering and automated machine learning to adaptively learn the structure-composition-property relationships of perovskite oxide materials for energy conversion and storage. Structure-composition-property relationships between stability and other features of perovskites are investigated. Extreme feature engineering is used to construct a great quantity of fresh descriptors, and a crucial subset of 23 descriptors is acquired by sequential forward selection algorithm. The best descriptor for stability of perovskites is determined with linear regression. The results demonstrate a high-efficient and non-priori-knowledge investigation of structure-composition-property relationships for perovskite materials, providing a new road to discover advanced energy materials.

Organic solar cells (OSCs) have experienced rapid development and achieved significant breakthroughs in power conversion efficiencies owing to the emergence of non-fullerene acceptors (NFAs) with ladder-type multiple fused ring structures. However, the high synthetic complexity and production cost of multiple fused ring NFAs hinder the commercial prospects of OSCs. In this context, the development of non-fused ring acceptors (NFRAs) with simple structures and facile synthesis has been proposed. In this mini review, we summarize the important progress in this field spanning from molecular design strategies to structure-performance relationships. Ultimately, with the aim of realizing the practical application of NFRAs in OSCs, we discuss the current challenges and future directions in terms of achieving high performance and low synthetic complexity simultaneously. These discussions provide valuable insights into the development of new NFRAs.

Due to the growth of the demand for rechargeable batteries in intelligent terminals, electric vehicles, energy storage, and other markets, electrode materials, as the essential of batteries, have attracted tremendous attention. The research of emerging organic electrode materials in batteries has been boosted recently to their advantages of low cost, environmental friendliness, biodegradability, and designability. This manuscript highlights and classifies several recent studies on organic electrode materials and lists their potential applications in various battery systems. Finally, the challenge and perspective of organic electrode materials are also summarized.

Fiber-shaped supercapacitors, which occupy minimal volume and possess remarkable flexibility, are particularly promising candidates for next-generation smart wearable devices. However, the state-of-the-art energy density and mechanical properties of fiber-shaped electrodes are far from satisfactory. Herein, hollow poly(3,4-ethylenedioxythiophene):polystyrene sulfonate thin-walled fibers (HPFs) are continuously prepared by coaxial wet-spinning. These HPFs combine a simple and high continuous preparation with high electrochemical performance and flexibility, owing to their hollow nature, small diameter (125 μm) and thin wall structure (8 μm). As a result, the HPFs display a specific areal capacitance of 115.2 mF cm^-2 at a current density of 0.3 mA cm^-2 with a high energy density of 9 μWh cm^-2 at a power density of 0.112 mW cm^-2. Furthermore, the HPFs maintain 81% of the initial capacitance after 10,000 cycles with ~100% Coulombic efficiency. More importantly, the specific capacitance is almost completely maintained after bending 3000 times at 180°.