Bulk Bismuth as a High‐Capacity and Ultralong Cycle‐Life Anode for Sodium‐Ion Batteries by Coupling with Glyme‐Based Electrolytes

Abstract

Sodium-ion batteries (SIBs) have attracted great interest for large-scale electric energy storage in recent years. However, anodes with long cycle life and large reversible capacities are still lacking and therefore limiting the development of SIBs. Here, a bulk Bi anode with surprisingly high Na storage performance in combination with glyme-based electrolytes is reported. This study shows that the bulk Bi electrode is gradually developed into a porous integrity during initial cycling, which is totally different from that in carbonate-based electrolytes and ensures facile Na transport and structural stability. The achievable capacity of bulk Bi in the NaPF -diglyme electrolyte is high up to 400 mAh g , and the capacity retention is 94.4% after 2000 cycles, corresponding to a capacity loss of 0.0028% per cycle. It exhibits two flat discharge/charge plateaus at 0.67/0.77 and 0.46/0.64 V, ascribed to the typical two-phase reactions of Bi ↔ NaBi and NaBi ↔ Na Bi, respectively. The excellent performance is attributed to the unique porous integrity, stable solid electrolyte interface, and good electrode wettability of glymes. This interplay between electrolyte and electrode to boost Na storage performance will pave a new pathway for high-performance SIBs.

A Porous Network of Bismuth Used as the Anode Material for High‐Energy‐Density Potassium‐Ion Batteries

“…Thet hin SEI films lead to small irreversible capacities and high Coulombic efficiencies.T he energy-dispersive X-ray spectroscopy (EDS) mappings suggest that they are mainly composed of K, P, and F, and are uniformly distributed in the surface of Bi. [17,18] After charge,t he signals of K2pd ecrease prominently as ar esult of the reversible depotassiation of Bi. The increased -CH 2 -s pecies originate from potassium alkoxides (RCH 2 OK), [4,17] which is evident by the peaks at 287.6 and 532.8 eV in the C1s and O1s spectrum ( Figure S14a, b).…”

Bi2S3 Nanorods Bonding on Reduced Graphene Oxide Surface as Advanced Anode Materials for Sodium‐Ion Batteries

“…During the discharge and charge processes in Figure e, reversible products NaBiS 2 , Bi metal, and Na‐Bi alloy were identified. According to these reaction products and other related references, it could be inferred that some part of the reactions is irreversible, and the mechanism in this system is a combination of conversion reaction and alloying reaction. The alloying reactions started from 0.67 V. Thus, four main redox reactions were part of the whole sodiation and desodiation process.…”

2D Elemental Nanomaterials Beyond Graphene

“…The formation of Na 3 Bi(c) buffers the volume expansion from NaBi (t)→Na 3 Bi (h) due to sodiation. The bulk Bi anode with a PF 6 ‐diglyme electrolyte shows a surprisingly high capacity of 400 mA h g −1 for Na storage with 94.4% capacity retention after 2,000 cycles . The Anode fabricated from Bi nanoparticles‐graphite composite shows a capacity of ∼160 mA h g −1 with 90% capacity retention after 10,000 cycles …”