Operando investigations of lithiation and delithiation processes in a BiVO₄ anode material

Abstract

Conversion and alloying reactions in BiVO4 as an anode material for lithium-ion batteries.

5D Total Scattering Computed Tomography Reveals the Full Reaction Mechanism of a bismuth vanadate lithium ion battery anode

“…8,20 Both area-summed data (increasing maximum r in the PDFs and appearance of Bragg peaks in conventional XRD) and maps from TSCT show that crystallite size increases with cycling. This has been observed in other bismuth metallate anodes (in both LIBs and NIBs) 12,19,21 , as well as for other conversion/alloying anode materials e.g. bismuth sulphide 22 .…”

“…Coin cell tests at a cycling rate of C/6.6 on the BiVO4/super P carbon/PAA binder composition used for the operando experiments showed that it performs as expected from our earlier studies. 12 The cells showed stable retained capacity of around 350 mAh g -1 between 250 and 500 cycles (supporting fig. S3).…”

“…The basic mechanism of lithium cycling in the BiVO4 based anode is confirmed 12 . BiVO4 converts irreversibly into Bi metal and LiyVO4.…”

“…Bismuth vanadate (BiVO4) is a promising LIB and sodium ion battery (NIB) anode material with high and stable capacity up to at least 1000 cycles. 4,12 Its cycling mechanism combines conversion and alloying reactions and the long cycle life is believed to be due to the lithium bismuth alloy (LixBi) particles being protected by a matrix of lithium vanadate (LiyVO4) which forms on decomposition of the initial bismuth vanadate. The LixBi/LiyVO4 composite formed on decomposition of bismuth vanadate in the first lithiation is amorphous, and its structure is still not fully understood despite XAS, diffraction and theoretical studies.…”

Understanding the (De)Sodiation Mechanisms in Na‐Based Batteries through Operando X‐Ray Methods

“…The use of structures from density functional theory (DFT) calculations (energy minimisations both of known structures from databases and invented structures produced, e. g. by replacement of certain atom types in a known structure) has already proved important in interpreting operando data from NIBs [42,43,171,206,218,224–226] . We expect such methods to find new applications as operando experiments develop further and come into wider use.…”