Construction and Modification of Copper Current Collectors for Improved Li Metal Batteries

Metallic Lithium have gained great attention for its high theoretical specific capacity. But continuous growth of Li dendrites upon cycling might cause low coulombic efficiency and serious security issues. Construction of advanced 3D Cu current collectors to regulate Li plating/stripping and improve battery performance is considered as one effective promising strategy. In this chapter, we will discuss the roles and requirements of current collectors in lithium metal batteries. Then methods (dealloying, powder-sintering and 3D printing) employed for construction of 3D Cu current collector and implementation of surface modification (lithiophilic sites and coating layers) will be illustrated. At last, future opportunities of Cu current collectors will be lifted out

Reversible K-Ion intercalation in CrSe2 cathodes for potassium-ion batteries: Combined operando PXRD and DFT studies

In the pursuit of more affordable battery technologies, potassium-ion batteries (KIBs) have emerged as a promising alternative to lithium-ion systems, owing to the abundance and wide distribution of potassium resources. While chalcogenides are uncommon as intercalation cathodes in KIBs, this study's electrochemical tests on CrSe2 revealed a reversible K+ ion intercalation/deintercalation process. The CrSe2 cathode achieved a KIB battery capacity of 125 mAh/g at a 0.1C rate within a practical 1- 3.5 V vs K+/K operation range, nearly matching the theoretical capacity of 127.7 mAh/g. Notably, the battery retained 85% of its initial capacity at a high 1C rate, suggesting that CrSe2 is competitive for high-power applications with many current state-of-the-art cathodes. In-operando PXRD studies uncovered the nature of the intercalation behavior, revealing an initial biphasic region followed by a solid-solution formation during the potassium intercalation process. DFT calculations helped with the possible assignment of intermediate phase structures across the entire CrSe2 – K1.0CrSe2 composition range, providing insights into the experimentally observed phase transformations. The results of this work underscore CrSe2's potential as a high-performance cathode material for KIBs, offering valuable insights into the intercalation mechanisms of layered transition metal chalcogenides and paving the way for future advancements in optimizing KIB cathodes

Constructing an active and stable oxygen electrode surface for reversible protonic ceramic electrochemical cells

The reversible protonic ceramic electrochemical cells (R-PCECs) can efficiently and cost-effectively store and convert energy at low-intermediate temperatures (400-700 oC). Their widespread commercialization is mainly limited by the challenges of oxygen electrodes due to the slow oxygen reaction kinetics and poor durability. In this study, we first enhance the reaction activity and surface stability of a double-perovskite PrBaCo2O5+δ (PBC) oxygen electrode by employing a fluorite-based Pr0.1Ce0.9O2+δ (PCO) catalyst coating. The PCO-coated PBC (PCO-PBC) oxygen electrode shows a much-reduced area-specific resistance of 0.096 Ωcm2 and good performance on a fuel-electrode supported single cell at 650 oC, displaying a typical peak power density of 1.21 Wcm-2 (in fuel cell mode) and a typical current density of 2.69 Acm-2 at 1.3 V (in electrolysis mode) with reasonable faradaic efficiencies and durability. PCO coating has significantly improved the surface exchange process, facilitated ion diffusion, and suppressed the Ba-segregation of PBC, as confirmed by the analyses of electrochemical performance and TEM.This study is financially supported by the Natural Science Foundation of Guangdong Province (2021A1515010395), the National Natural Science Foundation of China (22179039 and 22005105), the Fundamental Research Funds for the Central Universities (2022ZYGXZR002), the Pearl River Talent Recruitment Program (2019QN01C693), and the Introduced Innovative R&D Team of Guangdong (2021ZT09L392). K.P. appreciates the support of the China Postdoctoral Science Foundation Project (2020M682700). S.L. appreciates the support of the Science and Technology Innovation Program of Hunan Province (2021RC2007). ICN2 acknowledges funding from Generalitat de Catalunya 2021SGR00457. This study was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17. I1) and Generalitat de Catalunya. This research is part of the CSIC program for the Spanish Recovery, Transformation, and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094. The authors thank the support from the project NANOGEN (PID2020-116093RB-C43), funded by MCIN/ AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”, by the “European Union”. ICN2 is supported by the Severo Ochoa program from Spanish MCIN/AEI (Grant No.: CEX2021-001214-S) and is funded by the CERCA Programme / Generalitat de Catalunya.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2021-001214-S)Peer reviewe

Multicore-shell iron fluoride@carbon microspheres as a long-life cathode for high-energy lithium batteries

The study of multi-electron conversion cathodes is an important direction for developing next-generation rechargeable batteries. Iron fluoride (FeF3), in particular, has a high theoretical specific capacity (712 mA h g−1) and a low cost for Li storage. However, the FeF3 material suffers from poor conductivity, volume change and active material dissolution, resulting in voltage hysteresis and poor cycling and rate performance during electrochemical reactions. Here novel multicore–shell FeF3@carbon (C) composite microspheres with FeF3 nanoparticles embedded in carbon shells are developed through a bottom-up method and demonstrate smaller FeF3 particle size, a good carbon coating and superior maintenance of carbon shell integrity after fluorination and cycling as well. The FeF3@C/Li cells exhibit excellent electrochemical properties, offering a reversible capacity of 511.4 mA h g−1 at 0.2C after 250 cycles and outstanding cycle stability for 3500 cycles, with a capacity retention of 81% at 1C. It is worth noting that the carbon shell effectively inhibits the dissolution and diffusion of the active material and enhances the electrode reaction kinetics during charge/discharge reactions together with reduced core size. Overall, the sophisticatedly designed multicore–shell structure not only effectively improves the electrochemical properties of FeF3 but also offers a new idea for refining transition metal-based electrode materials.The authors gratefully acknowledge the National Natural Science Foundation of China (No. 51904344 and No. 52172264), the Natural Science Foundation of Hunan Province of China (Grant No. 2021JJ10060 and No. 2022GK2033), the Science and Technology Innovation Program of Hunan Province (2021RC2007) and the Fundamental Research Funds for the Central Universities of Central South University. ICN2 acknowledges funding from the Generalitat de Catalunya 2021SGR00457. The authors acknowledge support from the project NANOGEN (PID2020-116093RB-C43), funded by MCIN/AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”, by the “European Union”. ICN2 is supported by the Severo Ochoa program from Spanish MCIN/AEI (Grant No. CEX2021-001214-S) and is funded by the CERCA Programme/Generalitat de Catalunya.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001214-S).Peer reviewe