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Quasi-solid-state sodium-ion batteries (QSSNIBs) are regarded as a wise choice that balances practicality with security. However, further improvements is hindered by low ionic conductivity at room temperature. Herein, based on bacterial cellulose network, a high-strength gel polymer electrolyte (BC-GPE) for QSSNIBs is developed. The interwoven structure with abundant 3D ion transport passageways of BC-GPE make it display both high-strength (tensile strength of 36 MPa and maximum strain of 31.23%) and the inhibitory of "sodium dendrite" and "dead sodium" (an outstanding average coulombic efficiency of 98.3% and 190 cycles at 0.5 mA/cm2 and 1 mAh/cm2 in the Na/BC-GPE/SS cell). Furthermore, due to the excellent electrochemical properties of BC-GPE and the compatibility with NASICON type cathode Na3.5Mn0.5V1.5(PO4)3@C (NMVP@C), the QSSNIBs demonstrate high-rate performance and long cyclic life of 1250 cycles with a capacity decay rate of only 0.005%. All of these findings in this work can provide a novel insight for designing other high-strength GPEs and some new ideas for the potential applications of QSSNIBs in the near future. [ABSTRACT FROM AUTHOR]

The sodium-ion half/full cells display superior rate performance and impressive capacity retention with bacterial cellulose gel polymer electrolyte. [Display omitted] The irreversible consumption of active sodium in sodium-ion full-cells (SIFCs) becomes particularly serious due to the existence of unavoidable interface or side reaction, which has become the key to restrict the development of high-performance sodium-ion batteries (SIBs). Interface design and electrolyte optimization have been proved to be effective strategies to improve or solve this problem. In this work, on the basis of traditional organic liquid electrolytes, a novel gel polymer electrolyte with high ionic conductivity (1.13 × 10-3 S cm−1) and wide electrochemical stability window (~4.7 V) was designed and synthesized using bacterial cellulose film as precursor. Compared with the liquid electrolyte, the obtained electrolyte can endow better sodium storage performance in both half- and full-cells. When coupled with sodium hexacyanoferrate cathode and hard carbon anode, a capacity of 94.2 mA h g−1 can be obtained with a capacity retention of 75% after 100 cycles at a current density of 100 mA g−1, while those of with conventional liquid electrolyte can deliver a capacity of 99.0 mA h g−1 but only accompany 58% capacity retention under the same conditions. Significantly, when the current density increases to 800 mA g−1, their capacity difference reaches 23.4 mA h g−1. [ABSTRACT FROM AUTHOR]

Summary: Na2TiV(PO4)3 compound can be used as a cathode material for sodium‐ion battery for its good stability, high operating potential, and low material cost. In this work, a quasi‐solid sodium‐ion battery with Na2TiV(PO4)3@C as the cathode and Na‐form perfluorinated sulfonic resin (PFSA‐Na) membrane as the solid electrolyte were assembled and tested. It is worth mentioning that compared with liquid electrolyte battery, the quasi‐solid sodium‐ion battery displays better cycle and rate performance. At a different current density of 50, 100, 200, 500, and 1000 mA g−1, the quasi‐solid sodium‐ion battery shows specific capacities of 125, 110, 96, 73, and 45 mA h g−1, respectively. And after 300 cycles, the specific capacity still remains ~90 mA h g‐1, which is far better than liquid electrolyte battery (~70 mA h g‐1). The good result is due to the assembly of quasi‐solid batteries and the application of PFSA‐Na solid electrolyte. [ABSTRACT FROM AUTHOR]

A solid‐state polymer electrolyte (PFSA‐Na membrane) for solid‐state sodium‐ion batteries (SSIBs) to overcome severe safety issues caused by traditional liquid electrolytes is explored. The PFSA‐Na membranes, synthesized by an environmentally and economically friendly method, display high ionic conductivity, excellent thermal stability, and outstanding mechanical flexibility in a wide temperature range. SSIBs based on the PFSA‐Na membranes and Prussian blue cathode exhibit a superior rate performance of 87.5 mA h g−1 at 8 C and a durable cycling life of up to 1100 cycles at 1 C with only a slight capacity decay of ≈0.014% per cycle. Furthermore, due to the intrinsic advantages of the PFSA‐Na membranes, the cyclic performance of the proposed SSIBs is more stable than that of its liquid counterpart even at the rather low temperature of −35 °C. [ABSTRACT FROM AUTHOR]