Phenothiazine‐Functionalized Poly(norbornene)s as High‐Rate Cathode Materials for Organic Batteries

Abstract

Organicc athode materials are handled as promising candidates for new energy-storage solutions based on their transition-metal-free composition. Phenothiazine-based polymers are attractive owing to their redox potentialo f3 .5 Vv s. Li/Li + and high cycling stabilities. Herein,t hree types of poly(norbornene)s were investigated, functionalized with phenothiazine units through either ad irect connection or ester linkages, as well as their crosslinked derivatives. The directly linked poly(3norbornylphenothiazine)s demonstrated excellent rate capability and cycling stabilityw ith ac apacity retention of 73 %a fter 10 000 cycles at aC -rate of 100 Cf or the crosslinked polymer. The polymer network structure of the crosslinked poly(3-norbornylphenothiazine) was beneficial for its rate performance.

Polymer‐Based Batteries—Flexible and Thin Energy Storage Systems

“…Additionally, a thianthrene‐containing polymer was utilized for an all‐organic battery with poly(extended‐tetrathiafulvalene (poly(exTTF)). [ 64 ] Recently, also phenothiazine polymers [ 65,66 ] (Figure 3) and a polymer of the related phenoxazine [ 67 ] were applied as cathode materials and due to strong ππ‐interactions between the phenothiazine groups in the poly(vinylphenothiazine) PVMPT in their oxidized states, a high cycling stability, and rate capability was obtained. [ 68,69 ] Batteries based on these materials feature a self‐discharge of ≈10% within 3 days, which is comparable to other systems.…”

“…[ 68,69 ] Batteries based on these materials feature a self‐discharge of ≈10% within 3 days, which is comparable to other systems. [ 66 ]…”

Structure-induced optoelectronic properties of phenothiazine-based materials

“…Portable electronics are more present in our everyday lives than ever before, and with the additions, such as wearable electronics and advanced smartphones, technology is at present dependent on Li-ion battery technology to provide energy storage for most applications. 100,101 Combining organic molecules with the current battery technology could offer a solution for many of the problems, enabling high energy densities and high rates, while improving safety. 100,102,103 Organic materials are flexible and tunable for specialized uses but have mostly been able to manage only a limited number of redox cycles when tested in conventional or flow battery cells.…”

“…100,102,103 Organic materials are flexible and tunable for specialized uses but have mostly been able to manage only a limited number of redox cycles when tested in conventional or flow battery cells. 101,104 PTZ-Based molecules have shown promise in providing a solution capable of handling redox cycles equivalent to commercial Li-ion batteries. 104 The first application of polymeric PTZ as cathode active materials in Li-ion batteries was presented by Golriz et al 105 The p-p stacking of the closely packed phenothiazine groups bound by the polymer backbone was suggested to result in improved conductivity.…”

“…Most recently, the poly(norbornene)s were tested as the polymer backbone with N-methyl-PTZ functionalized side groups (95). 101 The performance of the molecules discussed in this paragraph is presented in Table 4 and the molecular structures are described in Fig. 16.…”