Huge Electron Sponge of Polyoxometalate toward Advanced Lithium-Ion Storage.

The huge polyoxometalate, N a 48 [ H x M o 256 V I M o 112 V O 1032 ( H 2 O ) 240 ( SO 4 ) 48 ] ({Mo 368 }), which can be prepared by a facile solution process and can be applied in lithium-ion storage applications as the anode. The large and open hollow nanostructure is promising to store a larger number of lithium ions and expedite the diffusion of lithium ions. A single {Mo 368 } nanocluster can transfer 624 electrons, referred to as a "huge electron sponge". Pure {Mo 368 } without any support materials exhibits very high capacities of 964 mA h g -1 with hardly any decay for 100 cycles at 0.1 A g -1 and still maintains 761 mA h g -1 after 180 cycles at 0.5 A g -1 , indicating great cycling stability. The {Mo 368 } anode provides excellent rate performance and reversibility during the lithiation/delithiation processes, which are contributed by both the diffusion-controlled process and the capacitive process. The capacitive contribution can reach 71.7% at a scan rate of 2 mV s -1 . The high D Li + value measured by GITT confirms the fast reaction kinetics of the {Mo 368 } electrode. The {Mo 368 }//NCM111-A full cell is practically applied to light LED lamps. These investigations indicate that {Mo 368 } nanoclusters are advanced energy storage materials with high capacities, fast charge transfer, and low-cost mass production for lithium-ion storage. Moreover, {Mo 368 } should be considered a clean energy material because there is no production of environmental pollution during the charge/discharge processes.