Unlocking ultrahigh-capacity and phase-transition-free V2O3 cathodes via lanthanum dopant engineering for robust aqueous zinc-ion batteries

The octahedral tunnel-like three-dimensional (3D) structure of V2O3 enables fast metal ion (de)intercalation and high capacity in aqueous zinc-ion batteries (ZIBs), but suffers from phase transition-induced structural degradation and capacity fading. Herein, we demonstrate that the undesirable phase transition of V2O3 can be effectively suppressed through a new La3+ doping strategy and its implementation as a robust ZIBs cathode. The introduced La3+ ions not only can increase cell volume and expand ion channels of V2O3 but also offer plentiful Zn2+ storage sites and promote the transport of Zn2+ ions and electrons. In particular, the doping of La3+ maintains the octahedral tunnel structure of V2O3 and prevents its phase transition during (dis)charge, which improves the cycle stability of the V2O3 cathode in ZIBs. By virtue of the above favorable factors, La-doped V2O3 electrode presents an impressive discharge capacity of 632.1 mAh g−1 at 0.1 A g−1 after 100 cycles with a capacity retention up to 93.1%. Even at 10 A g−1, its discharge capacity remains at 342.7 mAh g−1 after 1000 cycles with a capacity attenuation of solely 0.0069% per cycle. This work establishes rare-earth cation doping as a universal paradigm to reconcile structural stability and multi-electron redox activity in high-capacity battery electrodes.