A Single‐Phase, All‐Solid‐State Sodium Battery Using Na_3−xV_2−xZr_x(PO₄)₃ as the Cathode, Anode, and Electrolyte

Abstract

“Single‐phase” all‐solid‐state battery, based on Na3−xV2−xZrx(PO4)3 as the cathode, anode, and electrolyte, is reported. It successfully undergoes room temperature charge–discharge reactions based on the V3+/V2+ (anode) and V3+/V4+ (cathode) redox systems with insertion reaction. The interfacial resistance is essentially zero at the anode and cathode.

Single‐Phase All‐Solid‐State Lithium‐Ion Battery Using Li3V2(PO4)3 as the Cathode, Anode, and Electrolyte

“…The OCV of Li 3 V 1.6 Al 0.4 (PO 4 ) 3 was more stable than Li 3 V 2 (PO 4 ) 3 , which suggests that suppression of the electronic conductivity in the Al‐doped Li 3 V 2‐x Al x (PO 4 ) 3 sample contributed to the large discharge capacity. This is in good agreement with our previously reported results for a single‐phase sodium battery with Na 2.6 V 1.6 Zr 0.4 (PO 4 ) 3 , where a much higher discharge capacity than that with Na 3 V 2 (PO 4 ) 3 , and where the OCV of the Na 2.6 V 1.6 Zr 0.4 (PO 4 ) 3 cell was more stable than that for the Na 3 V 2 (PO 4 ) 3 cell . Therefore, both high ionic conductivity and low electronic conductivity are required for a single‐phase all‐solid‐state battery.…”

“…This is in good agreement with our previously reported results for a single-phase sodium battery 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 with Na 2.6 V 1.6 Zr 0.4 (PO 4 ) 3 , where a much higher discharge capacity than that with Na 3 V 2 (PO 4 ) 3 , and where the OCV of the Na 2.6 V 1.6 Zr 0.4 (PO 4 ) 3 cell was more stable than that for the Na 3 V 2 (PO 4 ) 3 cell. [10] Therefore, both high ionic conductivity and low electronic conductivity are required for a single-phase all-solidstate battery. Although the reason for the declined electronic conduction in Al-doped sample(Li 3 V 1.6 Al 0.4 (PO 4 ) 3 ) is still not clear, there is possibility of the band gap is increased by adding Al in Li 3 V 2 (PO 4 ) 3 .…”

“…F. Han demonstrated a proof‐of‐concept for a single‐material battery using a sulfide‐based high ionic conductor, Li 10 GeP 2 S 12 , as the electrolyte, anode, and cathode to eliminate interfacial resistance between the electrodes and electrolyte . On the other hand, we have recently reported a single‐phase all‐solid‐state sodium‐ion battery based on a single material using Na 3‐x V 2‐x Zr x (PO 4 ) 3 as the cathode, anode, and electrolyte . This NASICON (Na Super Ionic CONductor)‐phase Na 3‐x V 2‐x Zr x (PO 4 ) 3 exhibited much higher ionic conductivity than undoped Na 3 V 2 (PO 4 ) 3 and underwent charge‐discharge reactions based on the redox reactions of the V 3+ /V 2+ (anode) and V 3+ /V 4+ (cathode) pairs.…”

“…[9] On the other hand, we have recently reported a single-phase all-solid-state sodium-ion battery based on a single material using Na 3-x V 2-x Zr x (PO 4 ) 3 as the cathode, anode, and electrolyte. [10] This NASICON (Na Super Ionic CONductor)phase Na 3-x V 2-x Zr x (PO 4 ) 3 exhibited much higher ionic conductivity than undoped Na 3 V 2 (PO 4 ) 3 and underwent charge-discharge reactions based on the redox reactions of the V 3 + /V 2 + (anode) and V 3 + /V 4 + (cathode) pairs. Among the Na 3-x V 2-x Zr x (PO 4 ) 3 compounds with various Zr content (x), Na 2.6 V 1.6 Zr 0.4 (PO 4 ) 3 (x = 0.4) exhibited especially the best charge-discharge performance at room temperature because of its superior ionic conduction and low electronic conductivity, which suppresses electron leakage.…”

Single‐phase All‐solid‐state Silver Battery using Ag1.5Cr0.5Ti1.5(PO4)3 as Anode, Cathode, and Electrolyte

“…The NASICON (Na Super Ionic CONductor)‐type materials are well‐known as promising candidates for electrolyte and electrode . We have recently reported NASICON‐type single‐phase all‐solid‐state batteries that are made from a single material using Na 3 V 2‐x Zr x (PO 4 ) 3 , Li 3 V 2‐x Al x (PO 4 ) 3 , and Li 1.5 Cr 0.5 Ti 1.5 (PO 4 ) 3 . In the single‐phase battery, a single material can function as the anode, cathode, and electrolyte.…”