Energy Storage Materials最新文献

Ether based electrolyte exhibits extraordinarily high lithium-ion conductivity at low temperature due to inherent low melting point and strong coordination strength of ether solvents. However, such fascinating properties do not bring desired low-temperature electrochemical performances of lithium–sulfur (Li–S) batteries. One of the critical challenges is the tendency to generate massive Li polysulfide (LiPS) clusters at sub-zero temperature, which hinders mass transport and retards polysulfide lithiation during discharge. Declustering LiPSs at low temperature is a prerequisite endeavour to expedite the reaction kinetics. Lithium nitrate (LiNO₃) has been ubiquitously employed to protect Li anode, while its strong coordination strength to break LiPS clusters and generate charged LiPS species remains elusive. This work demonstrates the importance of cationic Li_δ[LiNO₃]^δ+ species that can facilitate the formation of charged LiPSs. Such charged LiPSs are, experimentally and theoretically, proved to promote the LiPS conversion kinetics at low temperature. It is expected to enrich LiPS solvation fundamentals and shed light on unique neutral molecule to charge LiPSs for facile LiPS conversion.

Polyimide (PI) has been recognized as a potential organic cathode for Li-ion batteries (LIBs) due to its programmable structural design, high theoretical capacity, and resource availability. However, the poor intrinsic electrical conductivity of PI means that PI-based cathodes of LIBs have inefficient energy storage performance, especially at high current densities. In this work, the molecular structure of PI is optimized to obtain a layer-stacked crystalline PI with significantly enhanced dipoles, denoted NT-B for the first time. The dipoles in this PI are induced by the electronegative carbonyl groups from the monomer biuret and further enhanced via a π-π layer stacking effect. This work is the first to verify that the co-directional dipole enhancement effect of biuret is surprisingly different from that of monomer urea. A series of ex-situ/in-situ and theoretical DFT simulations are carried out to understand the functional mechanism of such effects. The multiple enhancement effects of the dipoles synergistically promoting the generation of a strong built-in electric field (BIEF) within NT-B are proposed based on the results obtained. It is confirmed that this BIEF plays a significant role in accelerating electron transport, which enhances the electrochemical activity of LIB cathodes. This work provides a new idea for the structural design of high-performance PI cathodes for LIBs.

The emerging lithium (Li) metal batteries (LMBs) are anticipated to enlarge the baseline energy density of batteries, which hold promise to supplement the capacity loss under low-temperature scenarios. Though being promising, the applications of LMBs at low temperature presently are still challenged, supposedly relating to the inferior interfacial reaction kinetics, unsatisfactory solid-electrolyte interphase, sluggish ion transport, and uncontrollable Li plating/stripping behaviors. Recognitions and expeditions on such challenges of low-temperature LMBs remain to be further conducted. This review comprehensively analyses the primary challenges that the electrolyte, cathode and its interface as well as anode and its interface of LMBs are faced at low temperature. The physicochemical and electrochemical behaviors of LMBs (solvation/desovlation, ion transport, interfacial chemistry, etc.) as a function of temperature are statistically discussed. Furthermore, the recent advances on solving the low-temperature issues of LMBs are classified and evaluated by recording the capacity retention of full cells at subzero temperatures. Finally, recommendations and perspectives promoting the future development of low-temperature LMBs are proposed.

Elevating the working voltage has proven to be an effective strategy for enhancing the energy density of ternary layered cathode materials. However, the accelerated failure of secondary particle structure during high-voltage cycling hinders their practical application. Although some attempts have been exerted to address this issue by designing particle arrangement, these secondary structure modifications only provide the limited help to the structural failure problem. Herein, we focus on the cause and characteristic of secondary particle cracks, investigate their formation principle and development rule, and delicately propose a unique double-hollow secondary structure. The two hollow regions create an environment that facilitates the release of internal strain and reduces stress at grain boundaries, thus ensuring the homogeneous stress distribution within the secondary particles. Thereby, the formation of intergranular crack is effectively mitigated. Additionally, the hollow regions act as barrier layers to impede the crack propagation. The dual functions of this double-hollow structure efficiently maintain the tight connection among these primary particles, greatly boosting the high-voltage cycling stability. The designed material with double-hollow architecture exhibits an obvious capacity retention increase from 67.8 % (conventional structure) to 84.4 % at 1 C within 3.0-4.5 V after 300 cycles. This work demonstrates that the double-hollow structure can effectively address the key issues of crack occurrence and development, providing a novel structural design concept for the exploration of high-voltage cathode materials with superior stability.

Pairing nickel-rich layered oxide cathodes (e.g., LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811)) with silicon-based anodes (e.g., SiO_x-graphite) and simultaneously increasing the upper cut-off voltage (> 4.3 V vs. Li|Li⁺) offers a promising pathway to increase the energy density of LIBs. However, the instability of state-of-the-art electrolytes poses a notable challenge for high-voltage Li ion cells with SiO_x-based anodes due to abrupt cell failure. This challenge originates mainly from the restricted lithium transport due to a thick solid electrolyte interphase (SEI), followed by lithium metal plating on the SiO_x-Gr anode, which leads to a roll-over failure. In this study, we introduce an additive-based electrolyte designed to facilitate the formation of a stable SEI on SiO_x-Gr while protecting the SEI from attack by hydrofluoric acid and PF₆⁻. The electrolyte formulation comprises 1 M lithium hexafluorophosphate (LiPF₆) dissolved in ethyl carbonate (EC) and ethyl methyl carbonate (EMC) mixture (3:7 by wt.) with 5 wt.% fluoroethylene carbonate (FEC) and 1.5 wt.% sulfonyl diimidazole show the ability to suppress roll-over behavior and retain a capacity of 92 % at 1C and 20 °C.

Developing low Pt loading and high-activity oxygen electrocatalysts is necessary to promote large-scale fuel cell applications. By data-driven and density functional theory calculations, PtFeCoNiMnGa nano high entropy alloy (HEA) was synthesized through liquid-phase reduction and H₂ calcination method and loaded on carbon nano-tube (CNT). Due to high entropy, electronic modulation, and cocktail effects, PtFeCoNiMnGa HEA catalyst shows great catalytic activity in oxygen evolution/reduction reaction (OER/ORR). The PtFeCoNiMnGa/CNT showed a low overpotential of 243 mV for OER, and for ORR a mass activity of 1.12 A mg_Pt⁻¹ (5.3 times than Pt/C). Moreover, the PtFeCoNiMnGa/CNT showed high durability by maintaining 95 % of its initial performance for up to 50 h. In addition, the zinc-air battery assembled with PtFeCoNiMnGa/CNT as the cathode catalyst had an open-circuit potential of 1.52 V and an energy density of 130.6 mW cm⁻², and was able to operate stably for 120 h without any significant degradation.

Sodium metal batteries (SMBs) are promising candidates for next-generation high-energy-density storage devices, given their high theoretical specific capacity and low cost. Despite their potential, the path to commercialization presents several critical challenges. To satisfy the requirements of modern energy storage, SMBs must achieve substantial advancements in application versatility, safety, energy density, and fast charging capabilities. The electrolyte, as the pivotal component of SMBs, plays a crucial role in achieving these performance metrics. This paper provides a detailed and comprehensive overview of the significant challenges that SMBs encounter, particularly in extreme conditions characterized by wide temperature ranges, flame retardancy, high voltage, and high rate capabilities, and how the synergistic effects of salts and solvents in the electrolyte can be leveraged to regulate the thermodynamic, kinetic, and electrochemical behaviors of SMBs under these conditions. Additionally, the paper also presents an informed outlook on future developments, highlighting the potential pathways for advanced electrolyte design to enhance the overall performance and commercial viability of SMBs.