A new lithium‐rich layer‐structured cathode material with improved electrochemical performance and voltage maintenance. (29th July 2019)

• Record Type: Journal Article
• Authors: Tian, Xiaoqing; Liu, Shengzhou; Jiang, Xueqin; Ye, Fei; Cai, Rui
• Is Part Of: International journal of energy research. Volume 43:Number 13(2019)
• Page Start: 7547
• Page End: 7556
• Publication Date: 2019-07-29
• Subjects: cathode material -- co‐doping strategy -- Li2RuO3 -- lithium‐rich layered oxides; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.4724
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: Lithium‐rich layered oxides (LRLOs) are highly attractive cathode materials for next‐generation lithium‐ion batteries because of their high reversible capacity, but poor cycle performance and voltage decay are two main problems that strongly limit their practical applications. These challenges also apply to the Ru‐based LRLOs of Li2 RuO3 . The Li2 RuO3 cathode material is highly attractive because of their high conductivity and favourable electrochemical reaction kinetics. To overcome the problems associated with Li2 RuO3, in contrast to normal single atom doping, here, we propose a Na, Cr co‐doping strategy with the design of Li2− x Nax Ru0.95 Cr0.05 O3 ( x = 0, 0.02, 0.06, and 0.1) series materials. Cr doping increases capacity, and Na doping suppresses voltage decay. As a result, the discharge capacity of the optimal Li1.98 Na0.02 Ru0.95 Cr0.05 O3 sample over 240 mAh/g after 50 charge‐discharge cycles at 0.2 C is maintained, and the capacity retention reaches a value of 80.5% compared with 69.1% for the undoped Li2 RuO3 . The value of the voltage decay in the Li1.98 Na0.02 Ru0.95 Cr0.05 O3 sample is 125 mV after 100 cycles at a rate of 1 C, and the voltage decay is 188.4 mV for the undoped Li2 RuO3 . This finding will expand the scope for designing novel layered electrodes with excellent performance. Abstract : To effectively overcome the voltage deterioration and capacity loss of Ru‐based LRLOs with enhanced capacities, we report a strategy of the design of Na, Cr co‐doping Li2 RuO3 (Li2− x Na x Ru0.95 Cr0.05 O3 ) cathode materials, in which Cr increases capacity and Na suppresses voltage decay. As‐mentioned materials delivered the enhanced capacity, cycling stability and voltage maintenance. This work will open new scope for designing novel Li‐rich cathodes with excellent performance.