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The electrochemical properties of the organic radical battery (ORB) having a lithium metal anode and a cathode consisting of a nitroxide radical polymer poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) with 1M LiPF 6 as an electrolyte in ethylene carbonate (EC)/dimethyl carbonate (DMC) have been evaluated at room temperature. The cell, with a thin cathode of 17 µm thickness incorporating 40 wt.% of PTMA, exhibited the full theoretical specific capacity at current densities up to 10 C (~1 mA/cm 2 ). However, a decrease in the specific capacity and an increase in the ohmic resistance were observed at higher current densities. The cell performance was good even on repeated charge-discharge cycles as an excess of 85 % retention of the initial discharge capacity was observed. This was true even after 400 cycles. However, a gradual decrease in capacity, an increase in charge-discharge voltage separation, and an electrode/electrolyte interfacial resistance have been observed after a large number of cycles. The examination of the scanning electron micrographs of the cathode material revealed that prolonged cycling resulted in the agglomeration of PTMA particles. These in turn increased the resistance and decreased the capacity of the cell.

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A highly ordered mesoporous carbon, AlCMK, with an assembly of carbon rods and a bimodal pore system is used for sulfur encapsulation, and the AlCMK/S composite is observed to be able to accommodate volume expansion during a discharge process and recover its original structure when recharged. It is proved that the assembly structure of AlCMK makes it "breath" during the redox reaction of lithium and sulfur. Such a novel ability greatly benefits the maintenance of electrode construction during a repeated discharge-charge process. Moreover, a long heating time (e.g. 20 h) at 300 C in a two-step melt diffusion method is found to contribute to the uniform dispersion of sulfur in the AlCMK carbon matrix. Using this featured composite, a Li-S cell retains 627 mA h g À1 after 450 cycles at 0.1 C-rate with a coulombic efficiency close to 100% and also shows good rate capability up to 5 C-rate, demonstrating a significant improvement of reversible capacity and cycle stability of Li-S cells.