Realization of a 594 Wh kg⁻¹ Lithium‐Metal Battery Using a Lithium‐Free V₂O₅ Cathode with Enhanced Performances by Nanoarchitecturing

Abstract

attention due to its lowest redox potential (−3.04 V vs SHE) and an ultrahigh theoretical capacity (2061 mAh cm −3 and 3860 mAh g −1 ). [4] Inspired by this, when various conventional cathode materials, such as LiFePO 4 , LiCoO 2 , NCM622, and NCM811, are coupled with LMA, they can only deliver restrained specific energy at the material level (based on theoretical specific energy-LiFePO 4 : 560 Wh kg −1 , LiCoO 2 : 520 Wh kg −1 , NCM622: 690 Wh kg −1 , and NCM811: 750 Wh kg −1 ) due to the capacity limitations of conventional cathode materials (theoretical specific capacities-LiFePO 4 : 170 mAh g −1 , LiCoO 2 : 140 mAh g −1 , NCM622: 187 mAh g −1 , and NCM811: 203 mAh g −1 ). [5] Moreover, in actual systems, the theoretical energy is mostly halved because the theoretical capacities of cathodes are significantly decreased at the charge/discharge rates generally used. Under such a background, to realize actual high-energy lithium-metal batteries (LMBs) exceeding 500-600 Wh kg −1 , the exploration of new high-capacity and high-rate cathodes for rational matching with LMAs is needed, even expanding to lithium-free materials. When considering the LMB system, not only should excessive use of lithium in lithium-containing cathode materials be suppressed due to the high cost and limited resources but also lithium-free cathode materials are much more attractive for their higher theoretical specific capacities, such as intercalation-reaction based V 2 O 5 (294 mAh g −1 , based on an insertion of two lithium per formula unit) and MoO 3 (279 mAh g −1 ) and conversion-reaction based FeS 2 (894 mAh g −1 ), and elemental S (1672 mAh g −1 ). [6][7][8][9][10] Moreover, their high theoretical specific capacities lower the areal cathode loading mass, as the limited rate capability caused by the thick electrode increasing the ion diffusion length and underutilization of active materials can be alleviated. [11] For these reasons, some recent researches has been focused on the development of new types of LMA// high-capacity Li-free cathode batteries. [12][13][14][15][16][17] However, the unfavorable properties of conversion-type cathode materials, such as the inevitable volume change and voltage hysteresis due to bond breaking/reconstruction and loss of sulfur during cycling, consequently cause fast capacity fading and finally cell failure. [18,19] Unlike conversion-type lithium-free cathodes, V 2 O 5To realize a high-energy lithium metal battery (LMB) using a high-capacity Li-free cathode, in this work, nanoplate-stacked V 2 O 5 with dominantly exposed (010) facets and a relatively short [010] length is proposed to be used as a cathode. The V 2 O 5 nanostructure can be fabricated via a modified hydrothermal method, including a Li + crystallization inhibitor, followed by heat treatment. In particular, the enlargement of the favorable Li + diffusion pathway in the [010] direction and the formation of a robust hierarchical nanoplate-stacked structure in the modified V 2 O 5 improves the electrochemical kinetics and stability; as a resul...

Synthesis, structural and electrochemical properties of V4O9 cathode for lithium batteries

“…These electrochemical results are compared to amongst the best and most recent cycling performance reported in the literature on morphologically-optimized high-performance V 2 O5 that is made in a nano-plate stacked form, whereby the capacity is stabilized at 258 mAhg −1 (4.0–2.0 V; 50 mAg −1 ) ( Sim et al, 2023 ). If a nanocomposite of V 2 O 5 made by a hydrothermal method is synthesized in the presence of conductive reduced graphene oxide (rGO) scaffold then an even higher capacity of 280 mAhg −1 (4.0–2.0 V; 50 mAg −1 ) was observed ( Alsherari et al, 2023 ).…”