Stable quasi-solid-state lithium-organic battery based on composite gel polymer electrolyte and compatible organic cathode material

Enhancement of zinc-ion storage capability by synergistic effects on dual-ion adsorption in hierarchical porous carbon for high-performance aqueous zinc-ion hybrid capacitors

Aqueous zinc-ion capacitors (AZICs) are considered potential energy storage devices thanks to their ultrahigh power density, high safety, and extended cycling life. Carbon-based materials widely used as cathodes in AZICs face challenges, such as inappropriate pore sizes, poor electrolyte-electrode wettability, and insufficient vacancy defects and active sites. These limitations hinder efficient energy storage capacity and long-term stability. To address these issues, the B and F co-doped hierarchical porous carbon cathode materials (BFPC) are constructed through a facile annealing treatment process. The BFPC-2//Zn device exhibited high capacities of 222.4 and 118.3 mAh g-1 at current densities of 0.2 and 10 A g-1, respectively. Notably, the BFPC-2//Zn device demonstrated long-term cycling stability with a high capacity retention of 96.9 % after 20,000 cycles at 10 A g-1. Additionally, the assembled BFPC-2 based AZICs displayed a maximum energy density of 175.8 Wh kg-1 and an ultrahigh power density of 17.3 kW kg-1. Mechanism studies revealed that the exceptional energy storage ability and charge-transfer process of the BFPC cathode are attributed to the synergistic effect of B and F heteroatoms and the coupling effect between vacancy defects and pore size. This work presents a novel design strategy by incorporating B and F active sites into hierarchical porous carbon materials, providing enhanced energy storage capabilities for practical application in AZICs.

A bipolar organic molecule towards the anion/cation-hosting cathode compatible with polymer electrolytes for quasi-solid-state dual-ion batteries

Ion concentration and mobility are tightly associated with the ionic conductance of polymer electrolytes in solid-state lithium batteries. However, the anions involved in the movement are irrelevant to energy generation and cause uncontrolled dendritic growth and concentration polarization. In the current study, we proposed the strategy of using a bipolar organic molecule as the anion/cation-hosting cathode to expand the active charge carriers of polymer electrolytes. As a proof-of-concept demonstration of the novel strategy, a bipolar phthalocyanine derivative (2,3,9,10,16,17,23,24-octamethoxyphthalocyaninato) Ni(II) (NiPc-(OH)8) that could successively store anions and cations was used as the cathode hosting material in quasi-solid-state dual-ion batteries (QSSDIBs). Interestingly, peripheral polyhydroxyl substituents could build a compatible interface with poly(vinylidene fluoride-hexafluoro propylene-based gel polymer electrolytes (PVDF-HFP). As expected, NiPc-(OH)8 displays a high specific capacity of 248.2 mAh/g (at 50 mA g-1) and improved cyclic stability compared with that in liquid electrolyte. This study provides a solution to the issue of anion migration and could open another way to build high-performance QSSDIBs.

Bendable quasi-solid-state aqueous sodium-ion batteries operated at -30 °C

Aqueous sodium-ion batteries (ASIBs) have garnered considerable attention for large-scale energy storage because of inherent safety and the Na abundance. Nonetheless, the solidification of aqueous electrolytes under sub-zero conditions results in diminished ionic conductivity and increased viscosity, hindering the electrochemical performance and versatility of ASIBs. Herein, we introduce a novel freeze-tolerant ASIB using antifreezing ethylene glycol-polyacrylamide-sodium perchlorate hydrogel electrolyte, paired with new couple of Na3MnTi(PO4)3 cathode and Fe-based anode. The addition of ethylene glycol in the electrolyte enhances ionic conductivity at cold temperatures and optimizes electrode capacity by reduced hydrogen bonding within the water molecules and a decline in free water activity. The pronounced interaction between ethylene glycol and water, combined with the cooperative effect of the crosslinked polyacrylamide network, enables the hydrogel electrolyte to effectively suppress water solidification and maintain better water-retaining capability, achieving remarkable mechanical extensibility and good ionic conductivity (2.5 mS cm-1) at - 40 °C. Consequently, the ASIB equipped with hydrogel electrolyte delivers high energy density of 43.6 Wh kg-1 and retains 64 % at - 30 °C. Furthermore, the flexible ASIB demonstrates robust mechanical durability when bent or compressed, efficiently powering electronic devices even at - 30 °C. Our findings will pave the way for advancing low-temperature ASIBs with hydrogel-based electrolytes.

Boosting lithium storage in covalent triazine framework for symmetric all-organic lithium-ion batteries by regulating the degree of spatial distortion

Covalent triazine frameworks (CTFs) with tunable structure, fine molecular design and low cost have been regarded as a class of ideal electrode materials for lithium-ion batteries (LIBs). However, the tightly layered structure possessed by the CTFs leads to partial hiding of the redox active site, resulting in their unsatisfactory electrochemical performance. Herein, two CTFs (BDMI-CTF and TCNQ-CTF) with higher degree of structural distortion, more active sites exposed, and large lattice pores were prepared by dynamic trimerization reaction of cyano. As a result, BDMI-CTF as a cathode material for LIBs exhibits high initial capacity of 186.5 mAh/g at 50 mA g-1 and superior cycling stability without capacity loss after 2000 cycles at 1000 mA g-1 compared with TCNQ-CTF counterparts. Furthermore, based on their bipolar functionality, BDMI-CTF can be used as both cathode and anode materials for symmetric all-organic batteries (SAOBs), and this work will open a new window for the rational design of high performance CTF-based LIBs.

Technological Advances and Market Developments of Solid-State Batteries: A Review

Batteries are essential in modern society as they can power a wide range of devices, from small household appliances to large-scale energy storage systems. Safety concerns with traditional lithium-ion batteries prompted the emergence of new battery technologies, among them solid-state batteries (SSBs), offering enhanced safety, energy density, and lifespan. This paper reviews current state-of-the-art SSB electrolyte and electrode materials, as well as global SSB market trends and key industry players. Solid-state electrolytes used in SSBs include inorganic solid electrolytes, organic solid polymer electrolytes, and solid composite electrolytes. Inorganic options like lithium aluminum titanium phosphate excel in ionic conductivity and thermal stability but exhibit mechanical fragility. Organic alternatives such as polyethylene oxide and polyvinylidene fluoride offer flexibility but possess lower ionic conductivity. Solid composite electrolytes combine the advantages of inorganic and organic materials, enhancing mechanical strength and ionic conductivity. While significant advances have been made for composite electrolytes, challenges remain for synthesis intricacies and material stability. Nuanced selection of these electrolytes is crucial for advancing resilient and high-performance SSBs. Furthermore, while global SSB production capacity is currently below 2 GWh, it is projected to grow with a >118% compound annual growth rate by 2035, when the potential SSB market size will likely exceed 42 billion euros.