Recent Advances of Pore Structure in Disordered Carbons for Sodium Storage: A Mini Review.

Disordered carbons as the most promising anode materials for sodium ion batteries (SIBs) have attracted much attention, due to the widely-distributed sources and potentially high output voltage when applied in full cells owing to the almost lowest voltage plateau. The complex microstructure makes the sodium storage mechanism of disordered carbons controversial. Recently, many studies show that the plateau region of disordered carbons are closely related to the embedment of sodium ion/semimetal in nanopores. In this regard, the classification, characterization and construction of nanopores are exhaustively discussed in this review. In addition, perspectives about the controllable construction of nanopores are presented in the last section, aiming to catch out more valuable studies include not only the construction of closed pores to enhance capacity but also the design of carbon materials to understand Na storage mechanism.

Gelation of organic liquid electrolyte to achieve superior sodium-ion full-cells.

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.