New insights into the Li-storage mechanism in α-Ga2O3 anode and the optimized electrode design

Abstract Fundamental insights into Li storage mechanism in α-Ga 2 O 3 allow manipulating materials with improved electrochemical performance. Here, conversion reactions coupled with alloying/dealloying process are uncovered for Li storage in α-Ga 2 O 3 anode, on the basis of ex-situ XRD, XPS, SAED and EDS mapping results. Specifically, both processes are part of irreversible. α-Ga 2 O 3 decorated with amorphous carbon and graphene (α-Ga 2 O 3 @C@G) and nitrogen doping are successfully fabricated via a facile approach, showing distinctly improved performance compared with pristine α-Ga 2 O 3 and α-Ga 2 O 3 decorated with graphene (α-Ga 2 O 3 @G). In the Ga 2 O 3 @C@G, dual carbon improves the electronic conductivity and facilitates electrochemical reconstruction of the Ga 2 O 3 @C@G upon cycling that renders high lithium ion diffusion, giving rise to enhanced capacitive contribution for lithium storage. As a result, the Ga 2 O 3 @C@G exhibits high discharge/charge capacity of 458/447.3 mAh g −1 after 50 cycles at 0.1 A g −1 , with capacitive contribution of 59.2% for lithium ion storage at a scan rate of 1 mV s −1 .