Composite Li-ion battery anodes produced by partial reduction of mixed oxides

摘要

A new method based on the partial reduction of mixed oxides is demonstrated for creating ultrafine metal-ceramic composites for lithium storage. Mixed oxides containing a more noble metal selected to be capable of alloying with lithium at potentials useful as a Li-ion battery anode are partially reduced to form an electrochemically active metal-ceramic composite. Experimental results are compared in systems with slow oxygen diffusion (SbVO_4, AgVO_3 and Ag_2V_4O_(11)), fast oxygen diffusion (Sb_2Mn_2O_7 pyrochlore) and microphase-separation (Sn_(0.5)Ti_(0.5)O_2 rutile). Materials are characterized using XRD, SEM, and TEM, and electrochemical tests are presented. Reversible charge capacities of 200-350 mAh/g (1100-2200 mAh/cm~3) and first-cycle losses of <20% are found in systems tested to date.